Rebecca Sharp, a clever and ambitious social climber, maneuvers through the rigid hierarchies of 19th-century British society to secure her place among the elite. Driven by a desire for wealth and status, Rebecca navigates the complexities of the Napoleonic era, often manipulating those around her to achieve her goals. Her primary opposition comes from the entrenched social structures and the moral judgments of her peers, who view her opportunistic nature with suspicion. The narrative employs a third-person omniscient perspective, providing a satirical lens through which the vanity and hypocrisy of the upper classes are exposed.

Readers frequently highlight the sharp, biting wit that Thackeray employs to dismantle the pretensions of the Victorian era. Discussion often centers on the moral ambiguity of Rebecca Sharp, who remains one of literature's most debated anti-heroines. Critics often note that the pacing effectively balances personal drama with broader social commentary, keeping the reader engaged despite the length of the work. The atmosphere is consistently described as cynical yet deeply observant, providing a clear window into the vanity that defines the title. Many appreciate how the narrative avoids simple moralizing, allowing the characters' flaws to drive the plot forward in a realistic manner.