Augustine Washington Jr. (1720 – May 1762) was an American planter, military officer, politician, and the eldest surviving son of Augustine Washington and his first wife, Jane Butler Washington. He is best remembered as the older half-brother of George Washington and as a respected public servant in colonial Virginia. 

Augustine Washington Jr. was born in 1720 at the Washington family's Wakefield (Popes Creek) Plantation in Westmoreland County, Virginia. His father was one of Virginia's leading planters and businessmen, while his mother, Jane Butler Washington, died when Augustine was still a child. Following her death, his father married Mary Ball, making Augustine the older half-brother of George Washington and several other Washington children. 

As the eldest surviving son of Augustine Washington's first marriage, Augustine inherited substantial family lands and business interests. He became a successful planter and was involved in the management of iron-producing properties, including interests connected with the Accokeek Iron Furnace, one of colonial Virginia's important industrial enterprises. He also became a member of the Ohio Company, an organization promoting settlement and development west of the Appalachian Mountains. 

In 1743, Augustine married Anne Aylett, daughter of William Aylett and Anne Ashton Aylett of Westmoreland County. Together they had six children, four of whom survived to adulthood, including William Augustine Washington, who later became one of the executors of George Washington's estate. 

Like many prominent Virginians of his era, Augustine served in the colonial militia and held the rank of colonel. He was also active in public affairs and, in 1754, was elected to represent Westmoreland County in the Virginia House of Burgesses. He served until 1758, participating in the colony's legislature during the opening years of the French and Indian War. His service reflected the Washington family's long tradition of military and political leadership in Virginia. 

Although his younger half-brother George would eventually achieve worldwide fame, Augustine remained an important figure within the Washington family. After the death of their older brother Lawrence Washington, Augustine inherited Lawrence's interest in the Accokeek Iron Furnace. The brothers maintained family connections despite managing separate plantations and estates. 

Augustine Washington Jr. died in May 1762, at approximately 42 years of age, at Wakefield Plantation in Westmoreland County, Virginia. He was buried at Popes Creek, where generations of the Washington family were laid to rest. 

Today, Augustine Washington Jr. is remembered as a respected Virginia planter, legislator, and militia officer whose public service contributed to the political life of colonial Virginia. While history has often focused on his younger half-brother, George Washington, Augustine played an important role in preserving and expanding the Washington family's estates and continued the family's longstanding tradition of leadership in the colony.