"The Father, the Son, and the Holy Guest Star" is the twenty-first and final episode of the sixteenth season of the American animated television series The Simpsons.

In this episode, Marge enrolls Bart in Catholic school after he is expelled from Springfield Elementary for performing a prank.

On the road, Marge, Ned and Lovejoy try to bring Bart back to the "one true faith" – The Western Branch of American Reform Presbylutheranism – by taking him to a Protestant Youth Festival where Marge tries bribing him with rock music and paintball, only for Homer and Sean to arrive there in a motorcycle and sidecar; having been alerted by Lisa, who agrees with Homer and Bart's desire to join a new faith, and engage in a Mexican standoff with Ned and Lovejoy.

Mankind is waging war over whether Bart's teachings were about love and tolerance, or understanding and peace (and whether he was betrayed by Milhouse).

[6] Colin Jacobson of DVD Movie Guide thought the episode was a "lackluster finale" but said it was better than "Thank God, It's Doomsday", which also dealt with religion.

They thought of it as a great episode that dealt with the sensitive topic of religious tolerance, stating that "with a daring story, we can't help but remember when The Simpsons was an edgy hip show that would frequently shed a light on cultural complexes".

[9] L'Osservatore Romano, the daily broadsheet of the Vatican, praised the episode for taking up issues such as Christian faith and religion.