John Bailey Gage (February 24, 1887 – January 15, 1970) was an American attorney who served as mayor of Kansas City, Missouri from 1940 to 1946.

He made reforms following the collapse of the political machine of Thomas Pendergast.

[2] In 1930, he started the Gage and Hill law firm in the Bryant Building at 11th and Grand.

[3] After Pendergast pleaded guilty to income tax evasion charges in 1939, Gage, a Democrat, campaigned for mayor for the Citizens Association party consisting of both Democrats and Republicans.

He died on January 15, 1970, a month after being hit by a truck driver while walking to work at 11th and Grand Avenue in Kansas City.