William Ockleford Oldman (1879 – 1949) was a British collector and dealer of ethnographic art and European arms and armour. His business W.O. Oldman, Ethnographical Specimens, London was active between the late 1890s and 1913. Oldman purchased items from various sources including from auctions, directly from other collectors and dealers and also from many small British museums and historic houses. He held regular auctions to sell items and also reserved items for possible sale to particular private collectors, scholars, and heritage institutions. He maintained frequent correspondence with his network of collectors and he was often visited by museum professionals and scholars from institutions around the world. Oldman continued to deal in artifacts after 1913 but ceased to arrange auctions. Ethnographic specimens with a provenance to Oldman's business can be found in various public institutions around the world including the National Museum of the American Indian, Pitt Rivers Museum, the British Museum and others. Items were either collected directly from Oldman or were part of donations from other significant collectors who were clients of Oldman.
In addition to his business Oldman also had a substantial personal collection. His focus was on Oceania. He sold his private collection of Oceanic material to the New Zealand Government in 1948 and included some of his business records and collection information in the sale. The New Zealand Government transferred the legal ownership of this collection including all the records to the Museum of New Zealand Te Papa Tongarewa in 1992.