Mary Gay Scanlon (born August 30, 1959) is an American attorney and politician. A member of the Democratic Party, she has represented Pennsylvania's 5th congressional district in the United States House of Representatives since 2019. The district is based in Delaware County, a mostly suburban county west of Philadelphia, and also includes a southwestern portion of Philadelphia itself as well as slivers of Chester and Montgomery counties. Scanlon spent the final two months of 2018 as the member for Pennsylvania's 7th congressional district. She was elected to both positions on November 6, 2018. That day, she ran in a special election in the old 7th to serve out the term of her predecessor, Pat Meehan, and in a regular election for a full two-year term in the new 5th. She was sworn in as the member for the 7th on November 13, 2018, and transferred to the 5th on January 3, 2019.