Leonel Núñez (born August 14, 1983 in Jamoa Norte, Dominican Republic) is a pitcher in Major League Baseball who plays for the Florida Marlins. He bats and throws right-handed.

Núñez was originally signed by the Pittsburgh Pirates as an undrafted free agent on February 16, 2000. From 2001 to 2004, he was a mainly used as a starting pitcher in the Pirates system. On December 16, 2004, he was traded to the Kansas City Royals for catcher Benito Santiago.

After being traded to the Royals, he was converted to a full-time relief pitcher. He began the 2005 season with the Single-A High Desert Mavericks. He was promoted to the Double-A Wichita Wranglers after posting a 9.00 ERA in eight games. He had his contract purchased by the big league club on May 9, 2005, and made his major league debut on the same day.