Masashi is a masculine Japanese given name. Notable people with the name include:

• Masashi Abe (阿部 雅司, born 1965), Japanese skier
• Masashi Amenomori (雨森 雅司, 1930–1984), Japanese actor
• Masashi Ando (安藤 雅司, born 1969), Japanese animator and character designer
• Masashi Arikura (有倉 雅史, born 1967), Japanese baseball player
• Masashi Asaki (朝基 まさし, born 1970), Japanese manga artist
• Masashi Chikazawa (近澤 昌志, born 1982), Japanese basketball player
• Masashi Date (伊達 昌司, born 1975), Japanese baseball player
• Masashi Ebara (江原 正士, born 1953), Japanese voice actor
• Masashi Ebinuma (海老沼 匡, born 1990), Japanese judoka
• Masashi Endō (遠藤 雅, born 1974), Japanese actor
• Masashi Eriguchi (江里口 匡史, born 1988), Japanese sprinter
• Masashi Fujimoto (藤本 政志, born 1963), Japanese entertainer who lives in London
• Masashi Fujiwara (藤原 正司, 1946–2018), Japanese politician
• Masashi Goda (合田 雅吏, born 1969), Japanese actor
• Masashi Hamauzu (浜渦 正志, born 1971), Japanese composer
• Masashi Hirose (広瀬 正志, born 1947), Japanese voice actor
• Masashi Hosoya (細谷 将司, born 1989), Japanese basketball player
• Masashi Ishibashi (石橋 政嗣, 1924–2019), Japanese politician
• Masashi Itō (伊藤 正, 1921–2004), Japanese holdout
• Masashi Joho (城宝 匡史, born 1982), Japanese basketball player
• Masashi Kameda, Japanese mixed martial artist
• Masashi Kamekawa (亀川 諒史, born 1993), Japanese footballer
• Masashi Kato (加藤 [Katō] 真志, born 1970), Japanese freestyle swimmer
• Masashi Kawakami (川上 雅史, born 1972), Japanese boxer
• Masashi Kishimoto (岸本 斉史, born 1974), Japanese manga artist
• Masashi Kita, Japanese mixed martial artist
• Masashi Kitamura (北村 允志, born 1977), Japanese voice actor
• Masashi Kokubun (國分 将, born 1995), Japanese footballer
• Masashi Kudō (animator) (工藤 昌史), Japanese animator
• Masashi Kudo (boxer) (工藤 政志, born 1951), Japanese boxer
• Masashi Kuriyama (栗山 雅史, born 1988), Japanese volleyball player
• Masashi Mikami (三上 真史, born 1983), Japanese actor
• Masashi Mito (水戸 将史, born 1962), Japanese politician
• Masashi Miyamura (宮村 正志, born 1969), Japanese footballer
• Masashi Miyazawa (宮沢 正史, born 1978), Japanese footballer
• Masashi Motoyama (本山 雅志, born 1979), Japanese footballer
• Masashi Nagara (長良 将司, born 1977), Japanese fencer
• Masashi Nakano (中野 正志, born 1948), Japanese politician
• Masashi Nakashima (中島 勝司, born 1962), Japanese diver
• Masashi Nakayama (中山 雅史, born 1967), Japanese footballer
• Masashi Nishimori (西森 将司, born 1989), Japanese baseball player
• Masashi Nishiyama (西山 将士, born 1985), Japanese judoka
• Masashi Oguro (大黒[Ōguro] 将志, born 1980), Japanese footballer
• Masashi Oiso (大礒[Ōiso] 正嗣), Japanese Magic: The Gathering player
• Masashi Omiya (大宮 政志, born 1938), Japanese cyclist
• Masashi Onda (恩田 昌史, born 1939), Japanese field hockey player
• Masashi Otani (大谷 昌司, born 1983), Japanese footballer
• Masashi Otsubo (大坪 政士, born 1938), Japanese pole vaulter
• Masashi Owada (大和田 真史, born 1981), Japanese footballer
• Masashi Ozaki (尾崎 将司, born 1947), Japanese golfer
• Masashi Ozawa (小沢 正志, born 1947), Japanese professional wrestler
• Masashi Sada (さだ まさし, 佐田 雅志, born 1952), Japanese singer
• Masashi Shiga (志賀 政司, born 1939), Japanese basketball player
• Masashi Shimada (born 1971), Japanese golfer
• Masashi Shimada (comedian) (島田 まさし, original name 藤田 正 [Fujita Masashi]; born 1966), Japanese comedian
• Masashi Shimamura (島村 征志, born 1971), Japanese footballer
• Masashi Sugawara (菅原 正志, born 1962), Japanese voice actor
• Masashi Takeda (wrestler) (竹田 誠志, born 1985), Japanese professional wrestler
• Masashi Tanaka (田中 政志, born 1962), Japanese manga artist
• Masashi Tashiro (田代 まさし, 田代 政, born 1956), Japanese television performer
• Masashi Ueda (植田 まさし, original name 植松 正通 [Uematsu Masamichi]; born 1947), Japanese manga artist
• Masashi Ueda (conductor) (上田 仁, 1904–1966), Japanese conductor, bassoonist
• Masashi Usami, Japanese scientist
• Masashi Wada (和田 昌士, born 1997), Japanese footballer
• Masashi Wakasa (若狭 大志, born 1989), Japanese footballer
• Masashi Waki (脇 雅史, born 1945), Japanese politician
• Masashi Watanabe (渡辺 正, 1936–1995), Japanese footballer and manager
• Masashi Yamamoto (山本 政志, born 1956), Japanese film director
• Masashi Yamamoto (baseball) (山本 雅士, born 1994), Japanese baseball player