The Adopting Act of 1729 was an act of the Synod of Philadelphia that made the Westminster Standards, particularly the Westminster Confession of Faith, the official confessional statements for Presbyterian churches in colonial America. Presbyterian ministers were required to believe or "subscribe" to the "essential and necessary" parts of the standards, but defining what was essential and necessary was left to individual presbyteries to determine.
The act was a compromise between Scotch-Irish ministers, who preferred unqualified subscription to the confessions in order to maintain Reformed theology, and the New Englanders, who preferred less hierarchical church government and believed that requiring subscription violated the principle of sola scriptura.
The Adopting Act is significant to the development of Presbyterianism in the United States. Continued controversy over the meaning of subscription and interpretation of the Westminster Standards led first to the Old Side–New Side Controversy and later the Old School–New School Controversy. In the 19th and 20th centuries, the language of the Adopting Act would be used to justify increasingly broad interpretations of the standards.