The O'Brien class of destroyers was a class of six ships designed by and built for the United States Navy shortly before the United States entered World War I. The O'Brien class was the third of five classes of destroyers that were known as the "thousand tonners", because they were the first U.S. destroyers over 1,000 long tons (1,016 t) displacement.

The Aylwin class was a class of four destroyers in the United States Navy; all served as convoy escorts during World War I. The Aylwins were the second of five "second-generation" 1000-ton four-stack destroyer classes that were front-line ships of the Navy until the 1920s. They were known as "thousand tonners". All were scrapped in 1935 to comply with the London Naval Treaty.