Several sets of twins are important to the storylines of The Sims series:
- Angela and Lilith Pleasant of Pleasantview
- Dina and Nina Caliente of Pleasantview
- Joshua and Martin Ruben of Sim State University
- Samantha and Kimberly Cordial of Belladonna Cove
- Hugh Thanasia and Lou Thanasia of Strangetown (Both deceased)
These Sims appear in the Family bin:
- Beatrice and Benedick Monty of Veronaville
- Lola and Chloe Singles (Curious) of Strangetown
- Almeric and Aldric Davis of La Fiesta Tech
- Garrett and Georgia Newson of Magic (neighborhood)
- The unborn Ottomas babies of Weather (neighborhood)
- Jason and Jodie Larson of Bluewater Village
- Anita and Carlotta Lobos of Riverview
- Lucille and Nellie Spenster of Riverview
- Hyacinth and Violet Atkins of Bridgeport
- Possibly Lacy Darer and Macy Clay of Twinbrook
- Possibly Eveline and Henri Fouchier of Champs Les Sims
- Possibly Davy Cho and Dany Shue from Hidden Springs
- Abrielle and Abrianna King from Lucky Palms
- Lindy and Lanya Avilla from Starlight Shores
- Penelope and Martin Pepper from Sunlit Tides
- Joe and Jules MacDuff from Moonlight Falls
- Arvid and Edvin Oss from Aurora Skies
The Sims console versions:
- Olde Salty and Pepper Pete of SimValley.
- Murky and Misty Waters of SimValley.
- Bayou Boo and Crawdad Clem of Miniopolis.
- Sophie and Babbette Couture of Urbzville.
- Sofi and Rita Nelson from Moonlight Bay