Bergman's screenplay centres on a chapter in The Magic Lantern. He summed up the film in Aftonbladet as follows:

"The story is a childhood memory. I had – I believe - just had my eighth birthday and it's a Sunday at the end of July 1926. The family live in an indescribable Chehkov-esque summer house in Dalarna. There are lots of us: Mother, father, Aunt Emma, three children, 'Aunt' Märta, Maj the nanny (whom I love), the cook Lalla and a young female friend of the family called Marianne (whom I also love). Yet I love my beautiful mother most of all. On the Saturday afternoon my father arrives on the Stockholm train.."

The director was Ingmar Bergman's son, Daniel, from his marriage to Käbi Laretei. Sunday's Children was his feature film debut.