Margaret Adele Parker-Koscik (born 30 June 1949) is an Australian former track and field athlete who competed in the javelin throw.

At senior level she was twice runner-up at the Australian Athletics Championships, first in 1965 then again in 1971.

[1] Parker's sole major international achievement was a gold medal at the 1966 British Empire and Commonwealth Games held in Kingston, Jamaica.

She defeated former champion and fellow Australian Anna Pazera in the final, throwing the spear 51.38 m (168 ft 6+3⁄4 in) to top the podium.

[2] She married fellow Australian athlete Sig Koscik in 1972.