In the same year he married Evelyn Balfour, the sister of Arthur James Balfour who was to be a leading member of the Conservative Party for 50 years and Prime Minister of Britain 30 years later. Rayleigh had been a student at Cambridge with Arthur James Balfour and through him had met Evelyn.
Sa parehong taon na siya kasal Evelyn Balfour, ang mga kapatid na babae ng Arthur James Balfour na ay isang nangungunang kasapi ng konserbatibo Partido para sa 50 taon at Punong Ministro ng Britain 30 years mamaya. Rayleigh nagkaroon na ng isang mag-aaral sa Cambridge sa Arthur James Balfour at sa pamamagitan niya ay matugunan Evelyn.