Temple married Dorothy Osborne, daughter of Sir Peter Osborne and Dorothy Danvers, in 1654. It was a love marriage and the couple were noted for constancy during their long engagement: Dorothy resisted pressure from her family to accept any of several other more eligible suitors, including Henry Cromwell and her cousin Thomas Osborne, 1st Duke of Leeds. She and William outlived all of their nine children, most of whom died in infancy; the suicide of their adult son John in 1689 was the greatest tragedy of their lives. There were two grandchildren. Dorothy died in 1695.