Old Lyme is a coastal town in New London County, Connecticut, United States. The Main Street of the town, Lyme Street, is a historic district. The town has long been a popular summer resort and artists' colony. The town is named after Lyme Regis, England.
The US headquarters of Sennheiser is located in Old Lyme, as is Callaway Cars, the Florence Griswold Museum (including the Florence Griswold House), the Lyme Academy College of Fine Arts, and the Lyme Art Association. Old Lyme and its neighboring town Lyme are the namesake for Lyme disease.
The town of Old Lyme contains several villages, including Black Hall, Laysville, Lyme, Soundview, and South Lyme. The total population of the town was 7,603 at the 2010 census.