Kroy Biermann and girlfriend Jillian Green are keeping the faith amid plenty of family drama … attending church together in Alpharetta.

The former NFL linebacker and Jillian were photographed leaving services Sunday … taking their relationship from the hiking trail to the church pews.

Check out the pics — Kroy and Jillian appear relaxed as they chat in the parking lot before heading toward their car.

The outing comes just days after Kroy’s 15-year-old son, Kroy “KJ” Biermann Jr., was granted bond while facing seven felony charges tied to the alleged sexual assault of a female classmate.

And the hearing brought another troubling allegation … prosecutors claimed investigators previously found videos on KJ’s phone involving sexual activity with an underage relative … but KJ’s attorney pushed back on the way prosecutors characterized the matter.

As TMZ previously reported … KJ denies the current allegations, and his mom, Kim Zolciak, has publicly defended him.

As for Kroy and Jillian, their relationship has its own messy wrinkle — Jillian is the estranged wife of Kyle Mowitz, who is dating Kim.