Two of the most obvious themes are expressed in Austen's title; they are the consequences of pride and the consequences of prejudice.
Both Elizabeth and Darcy are guilty of prejudice. Elizabeth is guilty of being prejudiced in judging Darcy to be proud and arrogant, while Darcy is guilty of being prejudiced in judging those that he thinks are beneath his society. While Darcy may have been guilty of conceit when he first arrives at Netherfield, it is actually later proved that he does not possess any wrongful pride. He is rightfully proud of who he is as a person and proud of his lineage. In fact, he is so prideless as to be willing to sacrifice himself in order to rescue Lydia, all for the sake of preserving Elizabeth's honor. Hence, Elizabeth is proved to have wrongfully judged Darcy with prejudice when she concluded that Darcy is a prideful, despicable person.
Ironically, it is actually Elizabeth who has wrongful pride. In fact, after reading Darcy's letter defending his character, she shamefully chastises herself for taking such pride in her "discernment," meaning her ability to see and understand things (Vol. 2, Ch. 36). While Darcy has his own share of pride, it is not wrongful pride. His true character flaw is conceit, as he explains, his parents, though good people, raised him to be "selfish and overbearing; to care for none beyond [his] own family circle; to think meanly of all the rest of the world" (Vol. 3, Ch. 58). Pride, as Darcy also explains, indeed, has its place, so long as it is regulated pride and pride in one's genuine ability to be virtuous, as we see in his line, "Pride--where there is a real superiority of mind, pride will be always under good regulation" (Vol. 1, Ch. 11).
A third theme we see in Pride and Prejudice is class distinctions. Throughout the entire book, individuals are crossing class lines. In fact, class distinction is one reason for Darcy's character failings as well as the Miss Bingleys'. Darcy, being a gentleman descended of the noble class looks down on anyone from the working class, while the Bingley sisters, who have risen in wealth from the working class, seem to have forgotten their humble origins and look down on anyone else from the working class. However, as part of the theme, social classes are breached. Elizabeth, a gentleman's daughter with working class relatives marries Darcy, a gentleman with upper class relations.
Pride and Prejudice contains one of the most cherished love stories in English literature: the courtship between Darcy and Elizabeth.
Pride and Prejudice depicts a society in which a woman’s reputation is of the utmost importance. A woman is expected to behave in certain ways. Stepping outside the social norms makes her vulnerable to ostracism. This theme appears in the novel, when Elizabeth walks to Netherfield and arrives with muddy skirts, to the shock of the reputation-conscious Miss Bingley and her friends.
The theme of class is related to reputation, in that both reflect the strictly regimented nature of life for the middle and upper classes in Regency England. The lines of class are strictly drawn. While the Bennets, who are middle class, may socialize with the upper-class Bingleys and Darcys, they are clearly their social inferiors and are treated as such.