The Sons of Liberty were a political group made up of American patriots

Patriot (American Revolution)

Patriots is a name often used to describe the colonists of the British Thirteen United Colonies who rebelled against British control during the American Revolution. It was their leading figures who, in July 1776, declared the United States of America an independent nation...

 that originated in the pre-independence North American British colonies

Thirteen Colonies

The Thirteen Colonies were English and later British colonies established on the Atlantic coast of North America between 1607 and 1733. They declared their independence in the American Revolution and formed the United States of America...

. The group was formed to protect the rights of the colonists from the usurpations by the British government after 1766. They are best known for undertaking the Boston Tea Party

Boston Tea Party

The Boston Tea Party was a direct action by colonists in Boston, a town in the British colony of Massachusetts, against the British government and the monopolistic East India Company that controlled all the tea imported into the colonies...

 in 1773, which led to the Intolerable Acts

Intolerable Acts

The Intolerable Acts or the Coercive Acts are names used to describe a series of laws passed by the British Parliament in 1774 relating to Britain's colonies in North America...

 (an intense crackdown by the British government), and a counter-mobilization by the Patriots that led directly to the American Revolutionary War

American Revolutionary War

The American Revolutionary War , the American War of Independence, or simply the Revolutionary War, began as a war between the Kingdom of Great Britain and thirteen British colonies in North America, and ended in a global war between several European great powers.The war was the result of the...

 in 1775.
After 1765 the major American cities saw the formation of secret groups set up to defend their rights.