William Tinsley (7 February 1804 – 14 June 1885) was an Irish architect who immigrated to the United States in 1851. He and his family settled in Cincinnati where Tinsley received commissions to design several prestigious buildings in the Midwestern United States.
William, the younger son of Thomas Tinsley and Lucy Brough, was born in Clonmel, County Tipperary. In about 1820 he entered the family building business. Although baptised into the Church of Ireland, Tinsley converted to Methodism at the age of twenty-one. Following the death of his father in 1825, William took over the company and received several commissions from local landowners, notably to rebuild Darling Hill, seat of the Pennefather family. He studied the designs of church architect James Pain, and was made official architect for the Diocese of Lismore on Pain's death.
In 1851, following a decline in business after the Great Famine, Tinsle and his wife Lucy and their nine children emigrated to the US. They sailed from Waterford to New York via Liverpool before settling in Cincinnati. His first major commission in his adopted country was the original North Western Christian University building which he began in the Winter of 1852-53. He completed several other commissions, among them work for Rockwell, Kenyon (Ascension Hall), and Wabash colleges as well as Ohio Wesleyan University and Bascom Hall at the University of Wisconsin. His last major work was the Ohio State School for the Blind at Columbus, Ohio. Following his death in 1885, he was interred at Crown Hill Cemetery, Indianapolis.