Which act, passed in 1765, imposed a tax on all printed materials in the American colonies?

The act that imposed a tax on all printed materials in the American colonies in 1765 was the Stamp Act. This legislation marked one of the first direct taxes levied by Britain on the colonies, aiming to generate revenue to help pay off debt from the French and Indian War. Under this act, documents such as newspapers, legal papers, and even playing cards required a stamp that demonstrated the tax had been paid.

The significance of the Stamp Act was immense, as it sparked widespread unrest and organized opposition among the colonists, who argued that they should not be taxed without their consent—a principle famously summarized by the slogan "No taxation without representation." This effective mobilization led to protests, the formation of groups such as the Sons of Liberty, and ultimately contributed to the growing revolutionary sentiment that would culminate in the American Revolution.

Other acts mentioned, such as the Townsend Acts, Tea Act, and Intolerable Acts, occurred later and focused on different areas of taxation and control, illustrating the evolving conflict between the colonies and British Parliament leading up to the Revolution.