Inoue Masanao (井上 正直, November 26, 1837 – March 9, 1904) was a daimyō and official of the Tokugawa shogunate during Bakumatsu period Japan.

He inherited the leadership of the Inoue clan and the position of daimyō of Hamamatsu Domain on his father’s death in 1847.

In 1863–1864 he participated in the discussions within Edo Castle on the ending of Japan’s national isolation policy and the signing of the unequal treaties with the western powers.

In 1868, despite his background as a fudai daimyō and former Rōjū, he sided with the Imperial forces in the Boshin War of the Meiji Restoration.

Inoue Masaharu was married to a daughter of Matsudaira Tadakata, daimyō of Ueda Domain.