Robert Boyle was born into a Protestant family. His father was Richard Boyle, Earl of Cork, who had left England in 1588 at the age of 22 and gone to Ireland. Appointed clerk of the council of Munster by Elizabeth I in 1600, he bought Sir Walter Raleigh's estates in the counties of Cork, Waterford, and Tipperary two years later. Robert's mother, Catherine Fenton, was Richard Boyle's second wife, his first having died within a year of the birth of their first child. Robert was the seventh son (and fourteenth child) of his parents fifteen children (twelve of the fifteen survived childhood). Richard Boyle was in his 60s and Catherine Boyle in her 40s when Robert was born. Of his father Robert would later write [12]:-

He, by God's blessing on his prosperous industry, from very inconsiderable beginnings, built so plentiful and so eminent a fortune, that his prosperity has found many admirers, but few parallels.

Indeed, Robert was fortunate to have the richest man in Great Britain for a father although, one would have to say, the Earl of Cork had acquired his fortune by somewhat dubious means. He was imprisoned in England on charges of embezzlement at one stage and later was fined heavily for possessing defective titles to some of his estates.

The Earl of Cork and his wife believed that the best upbringing for young children, up to the time they began their education, could be provided away from their parents. Robert was sent away to be brought up in the country while his father continued to aim for higher and higher political success. The Earl of Cork lived for four years in his town house in Dublin. He was appointed a lord high justice in 1629 and lord high treasurer in 1631. However, during this time in Dublin Robert's mother died and some time after this Robert returned from his stay with his country nurse to rejoin his family.

Robert was sent, together with one of his brothers, to study at Eton College in England in 1635. At this time the school was becoming fashionable as a place where important people sent their sons. The headmaster was John Harrison and the two young Boyle brothers lived in the headmaster's house [10]:-