These are episodes that were rated TV-14, other than the normal TV-PG. Season 20 has the most TV-14 episodes with 7, and Season 21 has the second-most with 4, and Season 27 has the third-most [only half of the season has aired so far, subject to change].
Season 2
Season 6
- Treehouse of Horror V
Season 9
- Treehouse of Horror VIII
- Natural Born Kissers
Season 10
- Simpsons Bible Stories
- Monty Can't Buy Me Love
Season 11
- Little Big Mom
Season 13
- Weekend at Burnsie's
Season 14
- Three Gays of the Condo
Season 16
- Treehouse of Horror XV
- There's Something About Marrying
- The Father, the Son and the Holy Guest Star
Season 17
- The Bonfire of the Manatees
- The Seemingly Never-Ending Story
Season 19
- Treehouse of Horror XVIII
- Papa Don't Leech
Season 20
- Sex, Pies and Idiot Scrapes
- Treehouse of Horror XIX
- Dangerous Curves
- No Loan Again, Naturally
- Gone Maggie Gone
- Wedding for Disaster
- Four Great Women and a Manicure
Season 21
- Treehouse of Horror XX
- American History X-cellent
- Chief of Hearts
- Moe Letter Blues
- Judge Me Tender
Season 23
- The Man in the Blue Funnel Pants
Season 24
- The Day the Earth Stood Cool
- What Animated Women Want
Season 25
- Homerland
- Yellow Subterfuge
- Days of Future Future
Season 26
- Treehouse of Horror XXV
Season 27
- Halloween of Horror
- Treehouse of Horror XXVI
- Barthood
Season 28
- Friends and Family
- Treehouse of Horror XXVII