Margaret Joyce Cooper (18 April 1909 – 22 July 2002), later known by her married name Joyce Badcock, was an English competitive swimmer who represented Great Britain at the Olympics and European championships, and England at the British Empire Games, during the late 1920s and early 1930s.

In the 100-metre freestyle she finished together with Jean McDowell, but the judges gave the bronze medal to Cooper in a 3–2 vote.

When Los Angeles hosted the 1932 Summer Olympics, she won a bronze in the women's 4×100-metre freestyle relay.

Cooper was born in the British island colony of Ceylon (now Sri Lanka), where her father owned a tea plantation.

Their eldest son Felix Badcock won a bronze medal in rowing at the 1958 British Empire and Commonwealth Games in Cardiff, Wales and their younger son Francis 'David' M Badcock (born 1937), also rowed for the Thames RC and was a reserve for 1958 Commonwealth games crew in addition to rowing in the 1958 boat race.