Nyssa may refer to:
- the genus name for the tupelo tree
- Nyssa (name), a female name
- Nyssa (Doctor Who), a companion of the Fourth and Fifth Doctors in the long-running British science fiction series Doctor Who
- Nyssa Damaskinos, a vampire in the movie Blade II
- Nyssa Raatko, a Batman supervillainess
- Nyssa (Cappadocia), a Roman/late-Roman city, Turkey
- Gregory of Nyssa (born 335), 4th-century Christian bishop, theologian and saint
- Nyssa, Oregon
- New York State Sociological Association (NYSSA), an organization of sociologists and community activists studying and or working in New York State
- Nyssa High School, a high school located in Nyssa, Oregon, United States