Jason Biggs better learn the horah ... 'cause his dog turned 13 Thursday -- and his wife threw the cute pooch its own "bark mitzvah" to celebrate.
Like a true yenta ... Jason's wife Jenny Mollen documented the whole ceremony on her Instagram when she and Biggs took the dog -- named Teets -- to a temple to make things official.
The whole fam dined on challah afterward to commemorate the special day.
It's unclear if she guilted Teets into taking these photos. But c'mon ...