Nicole Melichar-Martinez (née Melichar; Czech: Nicole Melicharová, Czech pronunciation: [ˈmɛlɪxarovaː]; born July 29, 1993) is an American professional tennis player who specializes in doubles. On 3 July 2023, she peaked at world No. 6 in the WTA doubles rankings. She has also reached a career-high singles ranking of No. 400 in 2012.

Melichar has won 14 doubles titles on the WTA Tour and two WTA Challenger doubles titles as well as two singles and seven doubles titles on the ITF Circuit. She also has won one Grand Slam title, winning the mixed-doubles crown at the 2018 Wimbledon Championships with Austrian partner Alexander Peya.