Captain John Parker (July 13, 1729 – September 17, 1775) was an American farmer and military officer who commanded the minutemen who fought at the Battle of Lexington on April 19, 1775.

[3] On April 19, 1775, the British commander in Boston Thomas Gage dispatched an expedition of approximately 700 army regulars under Lieutenant Colonel Francis Smith to search the town of Concord for hidden rebel supplies and weapons caches.

When reports of the approaching British force reached Lexington overnight, men from the town and the surrounding area began to rally on the Common.

Conflicting stories arrived, and as the British regulars had spent much of the winter engaged in harmless route marches through the Massachusetts countryside, their exact intention was far from certain.

[6] When Smith became aware that the countryside had been alarmed and that resistance might be encountered, he sent a detachment of light infantry under Major John Pitcairn ahead of the main column.

The lopsided casualty list led to initial reports of a massacre, stories of which spread rapidly around the colony further inflaming the situation.

"[15] The United States Army Reserve (USAR), which consists primarily of part-time duty personnel, adopted John Parker as a symbol of their motto, "Twice the Citizen".