Kaoru Otsuki (Japanese: 大月 薰, romanized: Ōtsuki Kaoru; 6 August 1888 – 21 December 1970) was a Japanese woman known for being the second wife of Sun Yat-sen, the founder and first president of the Republic of China.

A year later, Sun proposed marriage again and Kaoru's father relented.

Kaoru and Sun's wedding ceremony was held in Yokohama in 1905 upon his return to Japan after two years.

Kaoru later remarried twice, first to Shūji Miwa (三輪 秀司), the younger brother of Shizuoka Bank president Shingorō Miwa (三輪 新五郎), and then to Motomune Sanekata (實方 元心), the Buddhist abbot of the Tokoji Temple in Ashikaga, Tochigi.

[3] Kaoru was reunited with her daughter Fumiko in 1955, after the latter visited the Tokoji Temple with her eldest son.