Ancillary K9 Dog Training (ancillaryk9.com) has a 5.0 out of 5 rating on OK.one, based on 11 user reviews collected here. It is listed under Animals & Pets and its reputation is excellent. Praise is nearly unanimous, with 100% rating it 4 stars or higher; 6 of them were added in the last 12 months. Last updated 2026-08-10.
If I could give Dion at K9 Ancillary more than 5 stars, I absolutely would.
When we first came to him, our Staffordshire Terrier had a very difficult past. He had a serious Grade 3 bite history and significant trauma from a previous owner, and we suspect he may have even been used in dog fighting. We were overwhelmed, scared, and honestly unsure if we would be able to keep him.
From day one, Dion never judged us or our dog. Instead, he took the time to teach us how to understand our dog’s behavior, build trust, and most importantly, keep ourselves and everyone around us safe in every situation. He didn’t just train our dog—he gave us the knowledge and confidence to become better owners.
One thing that truly sets Dion apart is that he cares about the whole dog, not just obedience. During one of our training sessions, he noticed our dog’s severe skin allergies and recommended switching him to a raw diet. Within just two weeks, the transformation was incredible. His skin cleared up, his allergies dramatically improved, and he became a much happier, healthier dog. That advice alone changed his quality of life.
Because of Dion, we made the decision to keep our dog instead of giving up. Looking back now, we can’t imagine our lives without him. That is something we will always be grateful for.
Over the course of this journey, Dion has become much more than a trainer. He has been a mentor, a source of encouragement, and a genuine friend who has supported us every step of the way. It’s rare to find someone who is this knowledgeable, compassionate, and truly invested in both the dogs and the people he works with.
If you’re looking for someone who will not only train your dog but also teach you how to build a lasting relationship with them, I cannot recommend Dion and K9 Ancillary highly enough. Thank you for helping us save our dog, giving us confidence, and changing all of our lives for the better. We are forever grateful.
L
Laura B. · 4 reviews · Experienced 2026-05-24 ·
★★★★★
I couldn’t be more pleased
At the time of this review I am halfway through my program with Dion/Ancillary K9. I have 2 Giant Schnauzers; a 3 year old female, Liesel, and a 7 month old male, Dieter. I had never done any formal obedience training with Liesel but had “gotten away with it” (really ??) because she is fairly easygoing and manageable . . . “just” challenged with impulse control & focus, not always fun to walk, and pretty lousy at recall. However, when it became apparent early on that Dieter is on the “wild child” spectrum (strong-willed, smart, sassy, independent, mouthy, exhibiting some reactive behaviors, and OBSTINATE), I knew I was in for a rough ride if I didn’t quit messing around and seek professional help early on.
After a ton of research and meeting with Dion, I decided to move forward with Ancillary K9 and haven’t looked back. I can’t say enough how happy I am with my decision.
Why?
1. Dion knows his stuff, no question. You won’t find many like him as far as his background and experience in dog psychology and behavior, and his success stories (as attested to by many, many clients) speak for themselves.
His insights into dog (and people!) behavior and the ability to speak to the whys and wherefores of what’s going on offer a dimension that is critical to accomplishing the goals you have for your dog- and yourself.
2) Dion is an outstanding teacher. His ability to get his points across using spot-on analogies and humor help to put you at ease and create a comfortable learning environment. He takes the time to ask thoughtful questions and gather information that enables him to tailor his instructions and recommendations for YOUR specific situation/needs, and he actively solicits questions and input. His explanations about the use of various tools (such as prong and e-collars) address their purpose/role/function and how, when used correctly, they can really benefit the training process in ways that the average dog owner doesn’t realize or understand. If you're like me, this will go a long way in helping to establish a comfort level with incorporating these tools into your training program.
3) I find Dion’s communication style to be refreshingly “real” and enjoy working with him; he cuts to the chase and tells it like it is, but is also supportive and encouraging. He’s clear about the need for YOU to put the work in with your pup if you want to be successful. It’s obvious that he’s committed to helping clients (both canine and human) build confidence and achieve success. His willingness to provide lifetime support speaks volumes about that commitment and isn’t something you’re going to find with very many programs.
While Liesel, Dieter and I still have a lot of work to do, I’m excited about the progress we’re making and am particularly thankful to be learning the tools to help me survive Dieter’s adolescent phase.
Working with Dion is one of the best decisions I’ve made, without a doubt. It’s an investment for sure, but there’s no question in my mind that the pay out will be well worth it.
For any of you who are serious about getting the help you need to make life better for you and your pup, I would encourage you to make the time to meet and talk with Dion about your situation and how he can help. It will be well worth your while, and, speaking from my experience, could help improve your relationship with your dog(s)- and possibly save your sanity.
Reply from Ancillary K9 Dog Training2026-05-25
Laura, thank you so much for taking the time to write such a thoughtful review. It has been a pleasure working with you, Liesel, and Dieter, and I’m really happy to hear that the training is already helping you feel more confident.
I’m excited to see how much more progress you all make as we continue and, thank you again for trusting me with your dogs! I really appreciate it.
J
Jennifer Larsen Brooker · 1 review · Experienced 2026-02-02 ·
★★★★★
Hiring Dion was one of the best…
Hiring Dion was one of the best decisions we ever made for our dogs.
Our dogs were reactive but fairly manageable—unless we encountered another dog that was lunging, jumping, or barking. That’s when everything escalated quickly. One of our dogs even redirected aggression toward our other dog, and I was bitten in the process. After being approached by several off-leash or out-of-control dogs, I knew that for our own safety, I had no choice but to address our dogs’ behavior. Other dogs’ behavior is unpredictable, but ours didn’t have to be.
When we first started working with Dion, I was extremely reluctant—and my husband was strongly opposed—to using training tools like the prong collar and e-collar. I had been conditioned to believe these tools were traumatic for dogs. Training began with leash walking, which I didn’t fully understand at first. I felt like I needed immediate help handling reactive encounters on walks, not focusing on structured leash work.
I’m so glad I trusted Dion’s education and process because that leash work became the foundation for our dogs’ incredible behavioral transformation. Within weeks, they were walking beautifully and were far less concerned with outside distractions. Through Dion’s training program, our dogs have become noticeably more relaxed and calm throughout the day. Many of our houseguests have even commented on how calm and balanced they are.
Although we didn’t specifically seek out Dion to address other reactive behaviors—like barking at dogs on TV or reacting to random noises—the training eliminated those unwanted behaviors as well.
I am now a supporter of using prong collars and e-collars when they are used correctly and responsibly. I was initially afraid of these tools, but they helped create a major behavioral shift in our dogs in a relatively short period of time. I firmly believe that avoiding these tools earlier only prolonged our dogs’ stress and anxiety.
If you are willing to put in the time and effort and follow Dion’s instructions, you will absolutely be rewarded with well-balanced pups. We are incredibly grateful for the transformation in our dogs and in our daily lives.
Thank you, Dion!!!
Reply from Ancillary K9 Dog Training2026-03-06
Jen, you put a lot of work into this, going above and beyond our lessons, and it shows. You built a solid foundation of structure and leash work giving your dogs the foundation they needed, and the results followed from there! I really appreciate your trust, consistency, and willingness to stay open to the process. Thank you for sharing such a thoughtful review.
Thanks to Dion my dog can now live a happy life and I can enjoy alongside him. Whether I need to go grab food or hike a trail, I can now trust my dog to listen and behave.
Dion has an almost magical ability to read my dog’s needs and he offers exactly the right solution to have it corrected. I cannot thank him enough for all the joy that I now get to experience with my dog.
Reply from Ancillary K9 Dog Training2026-01-05
Hi Ritwik, You've been a pleasure to work with and I genuinely appreciate all your had work and kind words. I'm always happy to lend a hand if you ever need anything!
C
Cecile · 2 reviews · Experienced 2025-09-01 ·
★★★★★
10/10 trainer
What can I say about Dion other than he’s fantastic and helped me and my pup tremendously! I rescued Rue about a year ago. She was super skittish, terrible on a leash, scared of; loud noises, men, bikes, thunder, the list goes on. And had an extremely high prey drive. My main goal was to reduce her overall anxiety and selfishly wanted to improve her recall off leash. Dion has helped with all that and more. I can confidently leave her off leash even with a squirrel nearby. She walks nicely by my side when we’re out. She seems way less anxious and just overall a more happy pup. Dion also taught me the skills to be a more confident and strong leader. Dion definitely knows what he’s doing and I can’t recommend his services enough. It’s been such a pleasure working with him!
Reply from Ancillary K9 Dog Training2025-11-07
Thanks so much for that awesome review. You've been great to work with...open, consistent, and committed to the process. Seeing how much more relaxed you and Rue have become together has been awesome. You did the hard work, and it's paid off!
N
None · 3 reviews · Experienced 2024-10-28 ·
★★★★★
Fantastic trainer!!
My wife and I rescued two new dogs last year in Dec 2023, a Rottweiler (Roman) and a Doberman (Gunner). We've had both breeds prior and she is a horse trainer so we've always had really well trained dogs. One of our two new dogs- Gunner the 120lb Doberman- was extremely pushy, lacked any structure, disregarded the rules, personal space, and discipline. He pulled excessively on the leash and was reactive towards other dogs, bikers, and joggers outside our fence. He was reactive on the leash during walks and he bit both my wife and I multiple times early after his adoption, so we just didn't feel safe with him any more. We spent 6 months trying treats, positive only training (punishment would encite aggression), youtube videos, prong collars, e-collars etc, and finally decided to find a professional for help as we wanted to start having kids soon and we were exhausted tip-toeing around just waiting for the next bite incident.
Through exhaustive research we found Dion and Ancillary K9 training. He was mentioned in multiple online forums as the "go-to" guy in Denver. He trains working dogs for scent work, bite work, protection work, as well as general obedience, reactivity, and aggression, so he understands large breeds and their behaviors. Many people had also mentioned that they had been to two, three, even four trainers first and they just weren't getting results and they finally ended up with Dion. We decided to skip all that time and money and effort and go straight to Dion as it was best for Gunner and our situation.
We have had 4 sessions thus far and my wife and I have said multiple times that we wish we had done this as soon as we adopted. Dion doesn't just tell you what to do, he helps you reframe your perception of the relationship you have with your dog, and the reasons WHY things work and why things dont work. He trains YOU to become your dog's leader and then YOU train your dog. Anyone can teach a dog to sit or do simple tricks, but it takes someone like Dion who understands dog behavior and psychology to truly modify and reframe desirable and undesirable behaviors.
I explained above that Gunner "was" all of these things and I used the past tense as he IS now a phenomenal dog. He's incredibly smart and with structure, rules, and effective tools and methods of communication, we have been able to build a fantastic relationship with him. He knows his place in our pack and we are able to lead him effectively. He is happier now and he has more freedom to join us wherever we go. He is no longer reactive on the leash or at our fence. He's at ease and calm even in chaotic environments, and he respects us and our heirarchy in the household. We get so many compliments on how well he's trained by the vet and people we see on walks all over town.
Gunner was rescued from a kill shelter in Texas and we had run out of options. Dion helped us learn the tools we needed to be effective leaders and to create a happy home for Gunner and every dog to come after him.
We can't thank you enough Dion!
Reply from Ancillary K9 Dog Training2025-10-11
Hey Nick, Thank you so much for taking the time to share such a thoughtful review! Working with you guys has been a pleasure and I really appreciate your trust in me to help get there.
J
Jordan · 2 reviews · Experienced 2024-01-08 ·
★★★★★
A New Leash on Life: How Dion's Expertise Transformed My Dogs World
Dion stands out as not only an exceptional dog trainer but also as a wonderful friend. My corgi, initially fearful and aggressive towards other dogs, found a new path under Dion's guidance. From our first consultation, Dion instilled a deep sense of confidence in me, teaching me effective ways to communicate and train my dog. Over the course of seven sessions and through consistent practice, the bond between my dog and me has grown immeasurably stronger, almost as if I have a completely new companion. The transformation in our relationship is a testament to the philosophy that the outcome of training hinges on your commitment. By following Dion's advice, asking questions, and maintaining consistent practice, I firmly believe anyone can significantly enhance their relationship with their dog. Dion's expertise is a game-changer.
Reply from Ancillary K9 Dog Training2024-01-12
Hey Jordan,
Wow, thanks for the awesome review! So happy to hear about you and your journey. You guys rocked it with your hard work and dedication. Anytime you need more tips or just wanna chat, I'm here. Keep up the amazing work!
C
Charles Michael Bennett · 2 reviews · Experienced 2023-04-03 ·
★★★★★
Ancillary K9
Review Ancillary K9
First off, Dion is an incredible dog trainer! The quality of our lives improved dramatically as a result of his teaching; and the outcomes? Amazing!!! Just Amazing!!!
I moved to Denver from San Francisco to reunite with my X wife and inherited her two dogs. Their behavior was so disruptive that I questioned whether I could actually reconcile our relationship. My X wife tried several dogs trainers with no noticeable results. Feeling hopeless; she just gave up.
I was so desperate to help, I began to search for high quality dog trainers. After careful consideration I chose Ancillary K9, and although the price was higher than most; reading all the rave reviews gave me a sense that this was likely a good choice. I soon realized, that this was a GREAT choice with “jaw-dropping” results!
After the first session, Dion gave us weekly homework and with each week, the dogs learned these skills. By the end of 6 weeks they were blowing our minds! They could sit, heel, and down-stay. They could sit while I walked away, they could stay down while we watch a movie or entertain guest. They successfully participated in the “Furry Scurry” 2 mile walk with hundreds of dogs around. We could take them patio restaurants, jazz concerts, we can park them outside a restaurant or store without incident. Sounds unreal doesn’t it? I have photos to post. Some photos will show a 3rd dog. She’s my 10 year old who came with me. We have all moved back to San Francisco now and are planning our Wedding. Perhaps the dogs will be part of the ceremony they’re so well behaved. Dion, you are the Master of your craft, You’ve helped me connect with these dogs and remind me why we I love these these wonderful animals….AND Dion, let’s face it….you saved our marriage! The Pups: Richocet, Riot, and Dakota all say thanks. Thanks so much.
Reply from Ancillary K9 Dog Training2023-07-17
Thank you for the amazing review, Charles! I'm thrilled to hear how much your life improved because of our dog training. I'm happy to hear results we achieved with Ricochet and Riot have had a profound impact on your relationship and happiness. I'm honored to have played a part in your journey and wish you all the best as you plan your wedding. Thank you for recommending us so enthusiastically!
A
Amanda Margolis · 1 review ·
★★★★★
Absolutely Worth It!!!!!
My experience with Ancillary K9 has been nothing short of amazing. Shortly after adoption, my dog Yeti showed fear and sometimes aggression towards other dogs. We tried group training classes but it was a disaster. I was really at a loss and knew I had to do more. I reached out to Ancillary K9 with Yeti's story and in that initial call, I was ready to get Yeti started ASAP.
Prior to our first session, I felt Yeti understood the "basics" of obedience. I also felt Yeti's challenges were more social than anything so I wasn't sure how more "training" would really help us. I NEVER would have guessed how much this course would've changed both of our lives. In the first session, Dion was extremely invested in understanding what brought us to the course and what challenges we were facing. Dion was not interested in applying blanket methods or focuses of the course - it was catered to both Yeti and myself.
This course has given both Yeti and myself so much more confidence. We laid pivotal building blocks and set goals. I immediately saw a change in both of us - more confidence in knowing how to react to a situation. Yeti has grown so much because of this course, all thanks to Dion!!
Reply from Ancillary K9 Dog Training2021-09-13
Thank you for sharing your story and the kind words!
B
Brooke Cameron · 1 review ·
★★★★★
We came to Dion as we were struggling…
We came to Dion as we were struggling with our 1-year-old dog's resource guarding habits. Although we still have some work to do, our dog has come so far in the 6 sessions we had with Dion. We have gotten so many compliments on how much better behaved our dog is from when we started. Dion helped us to understand not only how to train & communicate with our dog better, but more of why he was acting out in the first place. We are very thankful we found Dion, and we are excited to use what he has taught us to continue to strengthen our relationship with our dog!
Reply from Ancillary K9 Dog Training2021-07-26
Thank you for the lovely review, Brooke! It has been a pleasure working with you, KC, and Rusty.
N
Nicole E M Coutts · 1 review ·
★★★★★
If you are looking for professionalism
If you are looking for professionalism, kindness and growth within yourself and your canine companion-you have arrived at your destination. We were skeptical and concerned about our future with our beloved 1 1/2 yr old mini dachshund named Archie. We bought the 6 session package. He has learned all the commands and taking him for a walk is our favorite thing to do now! Archie is a much happier pooch and we are much happier parents. We highly recommend Dion. The investment is well worth a happy future.
~Jeff & Nicole Coutts
Reply from Ancillary K9 Dog Training2021-05-10
Thank you for the lovely review! I sincerely appreciate it. It's been a pleasure working with you Jeff, and Archie.
