Just married, I am active duty Navy and my wife is in the Army National Guard. Could I claim her as a dependent for BAH? Mil to Mil?

Yes she is your dependent.

If you both were Active Duty (Title-10), only one military member would receive BAH w/ dependents and the other would get BAH w/o dependents. She IS your dependent and should be claimed as such through finance and DEERS. You will receive BAH for the locale in which you are stationed. Depending on the circumstances, you may even be entitled to backpay of BAH. But you would have to speak to your human resource and finance departments.

Yes, you can. She is your dependant.