**Sidney Flanigan** (born 1995) is an American actress best known for her acclaimed debut role in Eliza Hittman's independent drama *Never Rarely Sometimes Always* (2020).

In the film, Flanigan plays Autumn Callahan, a teenager who travels with her cousin to New York City to have an abortion. Her performance, characterized by exceptional authenticity and profound emotional intensity, earned her critical acclaim, highlighting her ability to convey vulnerability and resilience. Flanigan is known for her naturalistic and measured acting style, often portraying young characters facing complex personal challenges. Her other credits include the gothic horror film *The Last Thing Mary Saw* (2021).