Mary Lou Piatek-Daniels (born August 6, 1961) is a retired tennis player from the U.S. who played on the WTA Tour during the 1980s.

She won her first pro title at Richmond, Virginia 1981, beating Sylvia Hanika and Sue Barker en route.

Piatek-Daniels made her ranking debut in February 1980 at no.

Her career wins include Robin White, Christiane Jolissaint, Kathy Horvath, Wendy White, Gigi Fernández, and Betsy Nagelsen.

This American biographical article related to tennis is a stub.