He was 83 and had Parkinson's disease.
Wesker, who wrote more than 40 plays that were translated into 18 languages, first gained prominence with a trilogy about the lives of Jewish socialist intellectuals: "Chicken Soup with Barley" (1958), "Roots" (1959) and "I'm Talking about Jerusalem" (1960).
He was known, together with writers including John Osborne and Brendan Behan, as one of the "angry young men" of the British stage in the 1950s - though he dismissed the label.
"There were quarrels and they were upsetting, but in a strange way there was so much love around, it overshadowed the distress," he told the BBC's "Desert Island Discs" program in 2006.
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Born on May 24, 1932, Wesker never went to college but instead had a string of jobs that informed his writing, including bookseller's assistant, farm laborer, kitchen porter and pastry cook, as well as service in the Royal Air Force in 1950-52.
In the stiff, upper-class world of British drama in the 1950s, Wesker was part of a wave of new voices who took on all subjects, the "kitchen sink" of drama. Together with playwrights like Harold Pinter, Wesker helped broaden the appeal of theater to a new generation.
His plays have experienced a revival of late, with "Chicken Soup" performed in 2011 at London's Royal Court Theatre. Dominic Cooke, the Royal Court's artistic director at the time, said Wesker understood theater "is always metaphorical, even when the social context of the play is realistic and detailed."
Wesker's other well-known plays include "Chips With Everything," based on his service in the RAF, and "The Kitchen," which draws on his days as a pastry cook. They were stories of ordinary people and real life. And he loved telling them well.