"A Nightingale Sang in Berkeley Square" is a romantic British popular song written in 1939 with lyrics by Eric Maschwitz and music by Manning Sherwin. Berkeley Square is a large leafy square in Mayfair, an expensive part of London. The Ritz Hotel referred to is also in Mayfair.

The song was written in the then small French fishing village of Le Lavandou—now a favourite resort for British holidaymakers and second-home owners—shortly before the outbreak of the Second World War. According to Maschwitz, the title was "stolen" from a story by Michael Arlen. The song had its first performance in the summer of 1939 in a local bar, where the melody was played on piano by Manning Sherwin with the help of the resident saxophonist. Maschwitz sang the words while holding a glass of wine, but nobody seemed impressed. In the spring of 2002, an attempt was made to find the bar where this song was first performed: it was hoped that a blue plaque could be set up. With the help of the local tourist office, elderly residents were questioned, but it proved impossible to identify the venue.