Ōtsu, Otsu, Ootsu or Ohtsu (written: 大津) is a Japanese surname. Notable people with the surname include:

• {{Nihongo|Hiromi Ōtsu|大津 広美||born 1984}}, Japanese speed skater
• Nobuyuki Otsu, Japanese engineer
• {{Nihongo|Toshio Ōtsu|大津 敏男||1893–1958}}, last Director of the Karafuto Agency
• {{Nihongo|Yūki Ōtsu|大津 祐樹||born 1990}}, Japanese footballer

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