"Mr. Moonlight (Ai no Big Band)" (Mr.Moonlight ～愛のビッグバンド～, Misutā Mūnraito Ai no Biggu Bando, Mr. Moonlight (Love's Big Band)) is the thirteenth single of J-pop idol group Morning Musume and was released October 31, 2001.

This single also marked the debut of the fifth generation members Ai Takahashi, Risa Niigaki, Makoto Ogawa, and Asami Konno.

The song exhibits heavy swing-style music influence, and the video featured the group dressed in outfits reminiscent of swing's peak era.

Lead vocals are Hitomi Yoshizawa, Maki Goto, and Natsumi Abe.

Inspiration for the cross-dressing costumes, theatrical style, and trademark staircase dancing appears to have been taken from Japan's Takarazuka Revue, an all-female musical theater troupe famous for its gender-bending performances.