Masako (written: 雅子, 正子, 真沙子, 真子 or まさこ in hiragana) is a feminine Japanese given name. Notable people with the name include:

• Empress Masako of Japan (雅子皇后)
• Princess Masako (恒久王妃昌子内親王), (1888–1940), 6th daughter of Emperor Meiji
• Masako Chiba (千葉 真子, born 1976), Japanese long-distance runner
• Masako Ebisu (恵比寿 まさ子, born 1945), Japanese voice actress
• Masako Hachisuka (蜂須賀 正子, born 1941), Japanese linguist
• Masako Hayashi (林 雅子, 1928–2001), Japanese architect
• Hōjō Masako (北条 政子, 1156–1225), later known as the "Nun Shogun"
• Masako Hozumi (穂積 雅子, born 1986), Japanese speed skater
• Masako Ikeda (池田 昌子, born 1939), Japanese voice actress
• Masako Ishida (石田 正子, born 1980), Japanese cross-country skier
• Masako Jō (城 雅子, born 1978), Japanese voice actress
• Masako Kato (加藤 雅子, born 1965), Japanese figure skater
• Masako Katsuki (勝生 真沙子, born 1958), Japanese voice actress
• Masako Katsura (桂 マサ子, 1913–1995), Japanese carom billiards player
• Masako Kisaki (木崎 正子, born 1943), Japanese middle-distance runner
• Minamoto Masako (源 晶子), (1552–1589), posthumous name of Lady Saigō, first consort of Tokugawa Ieyasu
• Masako Miura (三浦 雅子, born 1959), a voice actress
• Masako Mori (politician) (森 まさこ, born 1964), Japanese politician
• Masako Mori (singer) (森 昌子, born 1958), Japanese enka singer and former 1970s idol
• Masako Mori (writer) (森 真沙子, born 1944), Japanese novelist
• Masako Nakata (中田 正子, 1910–2002), Japanese lawyer
• Princess Nashimoto Masako of Japan (梨本宮方子女王), later Crown Princess Bangja of Korea
• Masako Natsume (夏目 雅子, 1957–1985), Japanese actress
• Masako Nozawa (野沢 雅子, born 1936), Japanese voice actress
• Masako Okawara (大河原 雅子, born 1953), Japanese politician
• Masako Sato (field hockey) (佐藤 雅子, born 1987), Japanese field hockey player
• Masako Sato (ice hockey) (佐藤 雅子, born 1973), Japanese ice hockey player
• Masako Seki (関 正子, died 2019), Japanese table tennis player
• Masako Sen (千 容子), former princess of Japan and daughter of Prince Mikasa
• Masako Sugaya (菅谷 政子, 1937–2021), Japanese voice actress
• Tokugawa Masako (徳川 和子), 5th daughter of Tokugawa Hidetada, the 2nd Tokugawa Shogun
• Masako Usui (笛吹 雅子, born 1968), Japanese announcer
• Masako Watanabe (わたなべ まさこ, born 1928), Japanese manga artist
• Masako Yoshida (吉田 雅子, born 1957), Japanese women's footballer