Lilla Nygatan (Swedish: Small New Street) is a street in Gamla Stan, the old town of Stockholm, Sweden. Stretching from the square Munkbron south to Kornhamnstorg, the street in intercepted by Yxsmedsgränd, Kåkbrinken, Schönfeldts Gränd, Tyska Brinken, and Lejonstedts Gränd, while forming a parallel street to Stora Nygatan and Munkbrogatan.
Together with Stora Nygatan, the street was part of a new city plan following the great fire of 1625, the street probably dating from 1630. It was being referred to as den nedre nye gathen ("the lower new street") in 1639, nedhre Nye gatun in 1641, nedre Nyegathon and nedre gathon in 1646, and Wästere Nyegathun ("western New street") in 1647. In 1660, the street was called Bryggaregatan (Bryggere Gaten, "Brewer's street") because of the number of brewers residing on its western side. Again, it is mentioned as nedrelangathun in 1667, while being called lilla Kongsgatan ("Small King's Street") in the early 18th century. The present name Lilla Nygatan became prevailing from 1720. Because Lilla and Stora Nygatan were often confused with each other, it was suggested in 1921 Lilla Nygatan should be renamed Postiljonsgatan ("Mailcoach Street") in reference to the post office, a proposal never put forward however.