What was the first Mickey Mouse cartoon to be made in color?

The first Mickey Mouse cartoon made in color was The Band Concert.

Released in 1935, The Band Concert was produced in three-strip Technicolor and marked Mickey’s official first color appearance in a publicly released film. It was directed by Wilfred Jackson and distributed by United Artists.

The story places Mickey at the head of a park concert band performing Rossini’s William Tell Overture. Donald Duck repeatedly disrupts the performance, and the music eventually summons a tornado that sweeps up the band, audience, and surroundings. Donald is the only speaking character.

A historical footnote causes occasional confusion: Mickey appeared in color in Parade of the Award Nominees in 1932, but that production was made for an Academy Awards ceremony and was not released to the public. The Band Concert is therefore conventionally recognized as his first official theatrical color cartoon. Its visual and musical staging also influenced later Disney shorts, including Symphony Hour.