Building Design Partnership (BDP) is a firm of architects and engineers employing over 1200 staff in the UK and internationally.

The firm was founded in 1961 by George Grenfell-Baines with architects Bill White and John Wilkinson, quantity surveyor Arnold Towler and eight associate partners: Brian & Derek Cobb, Keith Ingham, Peter Renninson, David Rock, Lorrie Rossant, N Keith Scott and Sid Tasker. The associates were made full equity partners in 1964. Grenfell-Baines was the first chairman.

BDP was the end result of a series of experiments in profit sharing and multidisciplinary working begun by Grenfell-Baines in 1941 with the Grenfell Baines Group. A 1962 policy statement committed BDP to "the principle of equal status for all professions". The firm expanded rapidly over the following decades and had 30 partners and 700 staff by the time of Grenfell-Baines's retirement in 1974.

BDP's principal offices, inherited from Grenfell Baines & Hargreaves, were in London, Manchester and Preston. By 1970, there were branch offices in Belfast, Glasgow and Guildford plus international offices in Memphis, Rome and Johannesburg.