This is often a confusing topic for pet parents. Sara wrote an article outlining all of the different titles (and what they mean) in an effort to help pet parents better understand the differences.  You can check out that article here:

What is the Difference Between a Dog Trainer and a Behaviorist?

The short answer is that you can think of dog trainers as those that focus on obedience (sit, down, stay) and canine behavior professionals as those that focus on why the animal is acting a certain way (and how to correct that behavior).