Namsan or Nam-san, literally "South Mountain" is a common name for Korean mountains and hills. Mountains known by this name include:
- Namsan (Chagang) in Chagang Province, North Korea
- Namsan (Haeju) in Haeju-si, South Hwanghae Province, North Korea
- Namsan (Eunyul-gun) in Eunyul-gun, South Hwanghae Province, North Korea
- Namsan (Seoul) in the Jung-gu district of Seoul, South Korea
- Namsan (Chungju) in Chungju City, North Chungcheong Province, South Korea
- Namsan (Sangju) in Sangju City, North Gyeongsang Province, South Korea
- Namsan (Gyeongju) in the heart of Gyeongju National Park, in Gyeongju City, North Gyeongsang Province, South Korea.