Ann Louise Gilligan (27 July 1945 – 15 June 2017) was an Irish theologian who taught at Saint Patrick's College, Drumcondra (part of Dublin City University).

[1] After leaving the convent, she worked in Spain and studied in Paris before being hired by St Patrick's College to teach theology in 1976.

[1][3] In 1981, while studying for her doctorate in theology at Boston College, she met and fell in love with fellow student Katherine Zappone.

[1] Together they fought Zappone and Gilligan v. Revenue Commissioners, a case which made global headlines and set off a decade of debate on marriage equality in Ireland.

[7] According to The Irish Times, An Cosán "was established by Gilligan and Zappone with the intention of bringing valuable community-based education to the Dublin suburb.