- Taeniosoma
- Tarrhomyos
- Tarrhomyos Riser, 1993
- Tatsnoskia Stimpson, 1857
- Tenuilineus
- Tenuilineus Riser, 1993
- Tetramys
- Tetramys
- Tetranemertes
- Tetranemertes Tshernyshev, 1992
- Tetraneuronemertes Sundberg, Gibson & Strand, 2007
- Tetrastemma
- Tetrastemma Ehrenberg, 1831
- Tetrastemmatidae
- Tetrastemmatidae
- Thallassionemertes
- Thallassionemertes
- Thermanemertes
- Thermanemertes
- Toeniosoma
- Tononemertes
- Tononemertes
- Tortus
- Tortus
- Tubonemertes
- Tubonemertes Coe, 1954
- Tubulanidae
- Tubulanidae
- Tubulans
- Tubulanus
- Tubulanus Renier, 1804
- Typhloerstedia
- Typhloerstedia Chernyshev, 1999
- Typhlonemertes Plessis, 1891