Tiny Tim is the crippled youngest child of Bob Cratchit, Scrooge's poor and ill-treated clerk. Scrooge's spirit-provided visions show him the meager Christmas celebrations of the Cratchit family, the sweet nature of Tiny Tim, and a possible early death for the child.

The story deals extensively with two of Dickens' recurrent themes, social injustice and poverty, the relationship between the two, and their causes and effects. It was written to be abrupt and forceful with its message, with a working title of "The Sledgehammer." The first edition of “A Christmas Carol” was illustrated by John Leech a politically radical artist who in the cartoon Substance and Shadow printed earlier in 1843, had explicitly criticised artists who failed to address social issues.

A Christmas Carol has been adapted to theatre, film, radio, and television countless times. On December 23, 1938, CBS broadcast a radio adaptation by Orson Welles' Mercury Theatre company, in the series The Campbell Playhouse. CBS broadcast a similar adaptation in 1939, as well as a reading before a live studio audience.

The story has also been used by successive generations of movie-makers and television directors to make their own points. In particular, many sitcoms have had episodes adapting or parodying the story for their Christmas episodes or specials.

Perhaps the most popular and critically-acclaimed film adaptation of the story was made in Britain in 1951. Originally titled Scrooge (and renamed A Christmas Carol for its American release), it starred Alistair Sim as Scrooge, and was directed by Brian Desmond-Hurst with a screenplay by Noel Langley.