Alfie (Michael Caine) is an attractive young Londoner who sees the world as his oyster and believes in enjoying himself without any regard for the possible cost to other people. He flits from woman to woman, taking care that there will be no strings attached.
When one of his regular girlfriends, Gilda (Julia Foster) becomes pregnant, he regards the child as entirely her responsibility, but as little Malcolm grows into an engaging toddler, Alfie finds himself becoming more emotionally involved. When he finds that Gilda has agreed to marry Humphrey (Graham Stark), a faithful admirer, he becomes ill and is sent to a sanatorium. He is unaware of the psychological nature of his problems, so brushes them aside and carries on as before. At the hospital he flirts with the nurses and becomes involved with Lily (Vivien Merchant), wife of one of the patients. This results in another pregnancy.
Alfie helps Lily get an (illegal) abortion from a seedy back-street doctor (Denholm Eliott). He suffers a further emotional trauma when he sees their still-born child, but goes on his way with a rich and merry widow, Ruby (Shelley Winters). He actually contemplates marrying her but she has acquired a new younger lover, and even his regular ‘birds’ do not seem to be as keen as they used to be.
Alfie is beginning to wonder – what’s it all about?