For her few scenes with Sir Michael Caine, Shelley Winters couldn't understand his dialogue at all, due to his strong Cockney accent, and had to wait until her leading man stopped moving his lips before responding with her lines.
On its original release, this movie had an all instrumental soundtrack, by Sonny Rollins. The Oscar nominated song, by Burt Bacharach and Hal David, was added for the American release, and to a U.K. re-release. For the U.K. re-release, the song was sung by Cilla Black over the end credits, which went to number nine on the British charts. For the U.S. release, the song was originally to be sung by Dionne Warwick over the end credits, but was replaced at the last minute by the version sung by Cher. Ironically, Warwick's version outperformed Cher's on the Billboard charts. Burt Bacharach produced Cilla's version, although George Martin insisted his be the only name to be credited.
As Alfie enters the Busy Bee Transport Café, the camera cuts away, and on return, a fresh advertisement has been placed on the background windows. This is advertising the Rolling Stones, a relatively new group on the scene, around the time this movie was shot.
A rarity in movies, Alfie (Sir Michael Caine) sporadically engages the audience by looking straight into the camera as he voices his thoughts, a technique known as "breaking the fourth wall". Lewis Gilbert would go on to direct Pauline Collins as the title character Shirley Valentine (1989), in which she also spoke her thoughts directly to the viewer.
The power station in the background where Humphrey (Graham Stark) gives his mother's gold ring to Gilda (Julia Foster) is the Lots Road Power Station with its original four chimneys, each two hundred seventy-five feet (eighty-four meters) tall. Opened in 1905 to supply power to the newly electrified Underground railways, it was converted from coal to oil in the 1970s, and due to the lower emissions from gas, the numbers of chimneys needed was reduced, so two were removed. The station stopped generating power in 2002.
Tippi Hedren, who was in London to film her scenes in a Charlie Chaplin movie, attended the London premiere on March 29, 1966. She sat right next to Director Lewis Gilbert when she fainted during the abortion scene.
In one scene of the film, one of Michael Caine's girlfriend was actually Paul McCartney's gal in real life. And when the latest was on the set during the preparation of the scene and saw his mate wearing a man's shirt very short, too short and showing her legs above the knees, he asked the producers for a longer shirt for her.