Lucy Tamlyn (born 1955) is an American diplomat who has served as the United States ambassador to the Democratic Republic of the Congo since February 2023.

Her father, Thomas Tamlyn, was a cardiologist who served in 1969 on the SS Hope, a ship that brought medical support to underserved areas.

Her mother, Ann Donaldson Tamlyn,[3] later ran unsuccessfully for a seat in the United States House of Representatives.

In her early career, she held assignments in Austria, Colombia, Mozambique, and domestically, in Washington, DC and New York City, NY.

She served as political officer in Brazil and represented the United States to the Food and Agriculture Organization in Rome.

[11] On July 27, 2018, President Donald Trump nominated Tamlyn to be the next United States ambassador to the Central African Republic.

On June 22, 2022, President Joe Biden nominated Tamlyn to serve as the United States ambassador to the Democratic Republic of the Congo.