udy and Mary was a Japanese multi-genre band formed in 1991 in Hakodate, Hokkaido by bassist Yoshihito Onda (恩田 快人, Onda Yoshihito?) and vocalist Yuki Isoya (磯谷 有希, Isoya Yuki?) with drummer Kohta Igarashi (五十嵐 公太, Igarashi Kōta?) and guitarist Taiji Fujimoto (藤本 泰司, Fujimoto Taiji?) completing the lineup the following year. Guitarist Takuya Asanuma (浅沼 拓也, Asanuma Takuya?) later replaced Taiji the following year. The band is known for their innovative punk, rock, and pop meldings of noisy but melodic music in the 1990s.

In 1992, they released their independent album Be Ambitious with an accompanying video on Chainsaw Records. They were picked up by Epic/Sony Records and released their first major label single, Power of Love in 1993. Their first debut major label album, J.A.M, was released in 1994. With each release they grew in popularity until they became one of the most popular and well-known bands in Japan. One of their songs, Sobakasu, was used as the first opening theme for the popular and famous anime TV series Rurouni Kenshin and sold over a million copies.

In all, they released seven albums, three compilation albums and twenty-two singles. Judy and Mary disbanded in March 2001 following the WARP Tour Final held at the Tokyo Dome. The concert is available on DVD.

Yuki is now enjoying a successful solo career as YUKI. Takuya is also currently a solo artist. Onda joined a band called the Hot Rod Crue, but since 2008, has been a member of the band ZAMZA N'BANSHEE.