Wren was born at East Knoyle in Wiltshire, the only surviving son of Dr. Christopher Wren (1589–1658), at that time the rector of East Knoyle and later Dean of Windsor.
As a sickly child, Christopher Wren would survive into robust old age. He was first taught at home by a private tutor and his father. After his father's appointment as Dean of Windsor in March 1635, his family spent part of each year there and of course the contacts with Royalty helped. He was at Westminster School from 1641 to 1646 some of his youthful exercises preserved or recorded showed that he received a thorough grounding in Latin; he also learned to draw and was "initiated" in the principles of mathematics by Dr William Holder, who married Wren’s elder sister Susan. During this time period, Wren manifested an interest in the design and construction of mechanical instruments.