Kate Marie Byrnes (born 1971[1]) is an American diplomat, who served as the United States ambassador to North Macedonia between July 2019 and September 2022.

[4][5] From 2007 through 2010, she was a public affairs advisor to the United States Mission to the North Atlantic Treaty Organization.

[6][9][10][11][12] A career diplomat, she had served as the deputy ambassador in Athens, and was the designated representative of the U.S. mission to the Organization for Security and Cooperation in Europe in Vienna.

[11][6] Addressing the United States Senate during her confirmation hearings, she averred her continuing commitment "to strengthen cooperation with (North) Macedonia as a strategic partner."

She highlighted that the Prespes agreement surmounted an historic hurdle, so its implementation is regionally important.