Lem's Bar-B-Q is a barbecue restaurant in the Chatham community of Chicago, Illinois, in the United States. The restaurant is known for its rib tips, which Eater has described as Chicago's "most famous rib tips."

Chatham is one of the 77 community areas of the city of Chicago, Illinois. It is located on the city's South Side. It includes the neighborhoods of Chatham-Avalon, Chatham Club, Chesterfield, East Chatham, West Chatham and the northern portion of West Chesterfield. Its residents are predominantly African American, and it is home to former Senator Roland Burris. Housing many city employees and other officials, Chatham has been a central area for Chicago's middle-class African Americans since the late 1950s.