Aleida Mathilde (Ada) van Keulen (13 January 1920, in Aalsmeer – 25 January 2010, in Laren, North Holland) was a Dutch woman who took part in the resistance during World War II. Van Keulen headed a boy scout group in Hilversum, the Heidepark Group, which became illegal during the war and carried out work for the resistance. She was also a courier for Hessels en Van Wilgenburg. On June 13, 1944, she was betrayed and arrested together with 27 other resistance fighters in Amsterdam. Among others, they included Jo Hessels, Hendrik van Wilgenburg, and , all of whom were imprisoned. Of the 27, only seven survived the war.