Niwa is a Japanese surname. Notable people with the surname include:
- Niwa clan, retainer clan of the Oda clan during the Sengoku period of Japan (1603 â 1868)
- Niwa Nagaaki, DaimyÃ
 of Nihonmatsu, 1796 â 1813
- Niwa Nagahide, DaimyÃ
 of Shirakawa
- Niwa Nagahiro, DaimyÃ
 of Nihonmatsu, 1868 â 1871
- Niwa Nagakuni, DaimyÃ
 of Nihonmatsu, 1858 â 1868
- Niwa Nagashige, DaimyÃ
 of Shirakawa, 1628 â 1638
- Niwa Nagatomi, DaimyÃ
 of Nihonmatsu, 1813 â 1858
- , Japanese curler, 1998 Winter Olympics participant
- Daiki Niwa (footballer), Japanese footballer
- Hideki Niwa, Japanese politician
- Koki Niwa, Japanese table tennis player
- Mikiho Niwa, Japanese actress
- , Japanese samurai and daimyÃ
Â
- Ryuhei Niwa, Japanese footballer
- , Japanese footballer
- Uichiro Niwa, Japanese diplomat and businessman
- Yasujiro Niwa, Japanese scientist
- Yuya Niwa, Japanese politician