Samuel Taylor Coleridge argued that it has one of the "three most perfect plots ever planned", alongside Oedipus Tyrannus by Sophocles and The Alchemist by Ben Jonson.

Allworthy returns from London after an extended business trip and finds an abandoned baby sleeping in his bed.

After searching the nearby village Mrs Wilkins is told about Jenny Jones, the young servant of a schoolmaster and his wife, as the most likely person to have committed the deed.

Jenny is brought before the Allworthys and admits being the one who put the baby in the bed, but refuses to reveal the father's identity.

Mr. Allworthy removes Jenny to a place where her reputation will be unknown and tells Bridget to raise the boy, whom he names Thomas, in his household.

After the marriage, Captain Blifil begins to show a coldness to his brother, who eventually feels obliged to leave the house for London.

Squire Western wants Sophia to marry Blifil to gain property from the Allworthy estate.

Tom's banishment seems to ensure that Sophia will be forced to marry Blifil, whom she finds odious, so she flees to avoid that fate.

Sophia and her maid arrive at the same inn, and Partridge unknowingly reveals the relationship between Tom and Mrs Waters.

Each book begins with a prefatory chapter directly addressing the reader, and the narrator provides a continuous commentary on characters and events.

Lady Bellaston, for instance, is widely believed to have been inspired by the real life character of Etheldreda Townshend.

But Ian Watt argues in The Rise of the Novel that Fielding did not aim at the "realism of presentation" of lifelike detail and psychology practised by authors such as Richardson.

"[9] The main theme of the novel is the contrast between Tom Jones's good nature, flawed but eventually corrected by his love for virtuous Sophia Western, and his half-brother Blifil's hypocrisy.

For instance, introductory chapters dwell extensively on bad writers and critics, quite unrelated to the plot but apologetic to the author and the novel itself; and authorial commentary on several characters shows strong opposition to Methodism, calling it fanatical and heretical, and falsely implying an association between Methodism and hypocrites such as the younger Blifil.

Characters take different sides over the rebellion, which was an attempt to restore Roman Catholicism as the established religion of England and to undo the Glorious Revolution.

At one point Sophia Western is even mistaken for Jenny Cameron, the supposed lover of Bonnie Prince Charlie.