She has been a plaintiff in multiple lawsuits related to civil and human rights, and has lobbied for legislation and greater policy protections for LGBTQ people.

[2] At age 13, she became the lead plaintiff in a 1999 class action lawsuit that alleged routine violence and psychological abuse was perpetrated against gay and lesbian children in New York foster care.

[2] At age 20, she lost a lawsuit she filed to have the cost of her gender affirmation surgery covered by New York City, after winning at the trial court level and losing on appeal.

[11] Between 2017 and 2018, Lopez filed multiple lawsuits related to her experience with Marsha's House, which was the only shelter for LGBTQ adults in New York City at the time.

[3][15] She has filed a lawsuit opposing a proposed beach development at the Christopher Street Pier,[16] seeking an assessment of the historic significance of the area.