Margaret A. Haley (November 15, 1861 – January 5, 1939) was a teacher, unionist, and Georgist land value tax activist,[1] who was dubbed the "lady labor slugger".

During her long career with the CTF, Haley fought to correct tax inequalities, increase the salaries of teachers, and expose unfair land leasing by the Chicago Board of Education.

Family financial troubles prompted Haley to begin teaching at age 16 at a country school in Grundy County, Illinois.

[5] After the Harper Bill’s defeat, Haley and Catherine Goggin strengthened their rule over the CTF, thus purging any opposition within the union and making it one of the most prominent workers' organizations in America.

Haley was hired as the CTF's permanent business representative in 1901 during her ongoing work investigating corporate tax evasion.

Haley and Goggin advocated that money be put into the school system; after years of advocacy, $600,000 was collected and directed towards teacher raises.

She played in instrumental role in Ella Flagg Young’s election to president of the National Education Association in 1910, which then paid greater attention to the needs of classroom teachers.

[citation needed] Margaret Haley died of a heart attack at Englewood Hospital in Chicago on January 5, 1939, aged 77.