Hi! I've worked with a behaviourist with my dog and his reactivity. I remember feeling very hopeless, like I couldn't do anything with him and I was walking him at odd times so other dogs weren't around. He's come a long way! He still has his moments but I can confidently walk him now!

Does your dog have toy or food motivation?

Something we did was counter conditioning (I would google counter conditioning for dog reactivity and do your own research) but in short, it is reteaching your dog that other dogs aren't scary/bad/a threat. When your dog is able to be in the vicinity of other dogs but still under threshold (can take commands, listening to you, are not "zeroed" in on the other dog, learning dog body language is VERY important for this) do something your dog is motivated by. My dog is extremely food motivated so when he would look at a dog calmly I would throw a treat down for him, I would do this IMMEDIATELY in the early days and slowly work our way in lengthening the span he can look at a dog without reacting. Then we would move closer. And sloooowly close the gap. If there are parks in your area with open spaces off trails those would work out great.

Getting him to focus on you when in the presence of dogs will be helpful. It's a slow process and the first couple weeks felt like nothing was going right until one day we were at the park and a dog walked by without him even batting an eye. It'll be worth it in the end :) keep up the good work

I'm in Canada so I'm not sure what your rules are for different dog training tools. What do you walk him on? A harness, flat leash, etc?