Lady Caroline Lamb (1785-1828) was an English aristocrat, the only daughter of the Frederick Ponsonby, 3rd Earl of Bessborough and Henrietta Ponsonby, the Countess.

Her social credentials also included being niece of Georgiana, Duchess of Devonshire, and cousin of Anne Isabella Milbanke.

She was born Caroline Ponsonby, and grew up as a tomboy, quite unable to read or write until her late adolescence due to her lack of a formal education. This was not uncommon for women of her time, despite her quite exalted position in society. Her considerable natural wit revealed itself in her early adult years, and she not only wrote prose and poetry, but also took to sketch portraiture. These courtly skills stood her in good stead.

In 1802 at the age of 17 she married William Lamb, an up-and-coming young politician, and heir to a viscountcy. Her union with Lamb produced an autistic son, and another child who died young. The loss of one child and the health problems of the surviving boy teamed with Lamb's consuming career ambitions to drive a wedge between the couple. There is some evidence (in an 1810 letter from Lady Caroline to Lady Melbourne) that Lamb was sexually promiscuous, and that he demanded the type of intemperate sexual shenanigans from his wife that would not be expected of a lady.

In 1812, Lady Caroline embarked on her well-publicised affair with Lord Byron (the main theme of the film, Lady Caroline Lamb). She had attracted the attention of the poet through her accomplished wit and vivacity, and he in turn obsessed over her, actively trying to destroy her marriage to Lamb so that he may have her to himself. She was 27 to his 24, a mother, quick witted and able to hold her own in the cut-and-thrust world of a politician's wife, but none of this served her well; she fell for his ploys, and became ensnared in his obsession for her. Byron's concept of romance was to fully possess the object of one's desire, right up until the moment that one became bored. Lady Caroline was heartbroken by her treatment and abandonment by Byron. It was she who described the poet as "mad, bad, and dangerous to know".

After her liaison with Byron, Lady Caroline enjoyed some success as a novelist. Her first novel, Glenarvon, was published anonymously in 1816, and included a thinly-disguised pen-picture of her former lover. She published further books, under her own name, during the following decade. In 1824, she accidentally came across Byron's funeral cortège on its way to his burial place, and this incident drove her to the verge of insanity.