Lori Ann Trahan (/trəˈhæn/ trə-HANN; née Loureiro; born October 27, 1973) is an American businesswoman and politician serving as the U.S. representative for Massachusetts's 3rd congressional district since 2019.

[1] The district covers Boston's northwestern suburbs, and includes Lowell, Lawrence, Concord, and Trahan's hometown, Westford.

[5] She graduated from Georgetown's Walsh School of Foreign Service with a bachelor's degree in comparative and regional studies in international relations.

[6][7] After college, Trahan worked for Marty Meehan, the U.S. Representative for Massachusetts's 5th congressional district, eventually becoming his chief of staff.

On March 4, 2019, The Boston Globe published an analysis of contributions to Trahan's campaign in the weeks before the 3rd congressional district's 2018 Democratic primary.

In the last days before the primary, Trahan put hundreds of thousands of dollars into TV advertising, and the Globe investigated the source of the money.

[14] The Ethics Committee voted unanimously to dismiss the inquiry on July 15, 2020, saying in its final report that it "did not find that Representative Trahan acted in violation of House Rules, laws, regulations, or other standards of conduct.

[23] On October 1, 2020, Trahan co-signed a letter to Secretary of State Mike Pompeo condemning Azerbaijan’s offensive operations against the Armenian-populated enclave of Nagorno-Karabakh and denounced Turkey’s role in the Nagorno-Karabakh conflict, and criticized "false equivalence between Armenia and Azerbaijan, even as the latter threatens war and refuses to agree to monitoring along the line of contact.

In January 2023, Trahan was one of 13 cosponsors of an amendment to the Constitution of the United States extending the right to vote to citizens sixteen years of age or older.