I get asked a lot if service dogs are tax deductible and sometimes I get asked if emotional support animals are, as well.
The answer is that service dogs can be tax deductible, if you itemize and deduct medical expenses. You can read more about that here, in an article written by my accountant.
Emotional support animals are not tax deductible under the current IRS rules. The IRS basically uses the ADA definition of a service dog, and that does not include emotional support animals.