Sinfin is a suburb located on the southern outskirts of Derby, Derbyshire, in the United Kingdom. It is situated approximately 3 miles (4.8 km) southwest of the city centre. The local ward encompasses both Sinfin and the neighboring area of Osmaston, which together had a population of 15,128 as of 2011.
Historically, Sinfin and Osmaston were independent villages that were eventually absorbed by the expansion of Derby. The two suburbs are distinguished by their architectural history; Osmaston is characterized by inter-war housing developments, while much of the residential housing in Sinfin dates to the post-war period. An industrialized area dominated by the Rolls-Royce works lies between the two suburbs.