Elliot, known for his work on Netflix superhero series The Umbrella Academy, said: “As I watch the movement of these bills attacking trans youth across the US, especially this week in Florida, Alabama, Texas and North Dakota, I am thinking of my trans siblings and the collective pain that our community must endure to battle again and again for our right to exist.
“These bills are upsetting, cruel and exhausting.”
The 34-year-old added: “Call your representatives. Tell them to oppose legislation that discriminates against us. Tell them our access to health care is an inalienable human right. Tell them to let trans kids play sports. Tell them that #TransPeopleBelong – we always have, and we always will.”
Elliot also shared a picture of himself holding up a sign reading “protect trans kids”.
This year has seen a record number of anti-transgender bills introduced in the US, according to the Human Rights Campaign, an LGBT advocacy group.
Transgender rights have emerged as a fraught issue in the culture wars.
Earlier this month Arkansas became the first US state to outlaw gender-affirming medical treatments or surgery for minors.
Those who back restrictions on transgender women in sports say they are essential to maintain fair competition for female athletes, while critics argue they unfairly target the transgender community and are not based on science.