Joe Serna Jr. (September 3, 1939 – November 7, 1999) was an American educator and civil rights activist who served as the 52nd mayor of Sacramento, California from 1992 until his death in 1999.

Serna organized a caravan from Sacramento to march in Chávez's funeral and renamed a park in front of City Hall to Cesar E. Chavez Plaza.

Serna died of kidney cancer on November 7, 1999, aged 60, while in office in Sacramento, California; Jimmie R. Yee presided over the remainder of his term.

The Joe Serna, Jr. EPA Building (near City Hall in downtown Sacramento) has been named the most energy-efficient high rise in the United States by Energy Star.

Serna is also, to date, the most recent mayor of Sacramento to eulogize a former California governor, delivering the final remarks at the funeral mass of Pat Brown in 1996 at the Blessed Sacrament Cathedral, which was presided over by then-governor Pete Wilson, whose term also ended in 1999, and celebrated by then-Bishop William Weigand.