Same sex may refer to:
- A phrase used in the discussion of sex or gender
- Gonochorism, the state of having just one of at least two distinct sexes in any one individual organism
- Homosexuality, the romantic attraction, sexual attraction or sexual behavior between members of the same sex or gender
- Sex segregation, the physical, legal, and cultural separation of people according to their biological sex
- Same-sex education, the practice of conducting education where male and female students attend separate classes
- Same-sex marriage, the marriage between two people of the same sex
- Same-sex relationship, a relationship between two persons of the same sex, in diverse forms