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

Melichar has won thirteen doubles titles on the WTA Tour and one WTA Challenger doubles title 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.