Samuel Augustus Maverick (July 23, 1803 – September 2, 1870) was a Texas lawyer, politician, land baron and signer of the Texas Declaration of Independence. His name is the source of the term "maverick", first attested in 1867. He was the grandfather of Texas politician Maury Maverick, who coined the term gobbledygook (1944).

Samuel Augustus Maverick was the oldest son of Samuel Maverick, a Charleston businessman, and his wife Elizabeth Anderson. His Maverick ancestors had arrived in the New World in 1624, before emigrating to Barbados and later to Charleston. After his paternal grandfather died, in 1793 his grandmother, Lydia Maverick (née Turpin), married American Revolutionary War general Robert Anderson. In October 1802, his father married Anderson's daughter Elizabeth, and nine months later, on July 23, 1803, Maverick was born at his family's summer home in Pendleton District, South Carolina. To his family, Maverick was known as "Gus". Over the next four years the family lived in Charleston, and his mother bore four more children, one of whom, Robert, lived less than a day. In September 1809, his sister Ann Caroline died of yellow fever. His father, having watched his ten siblings succumb to the same disease as children, moved his family permanently to Pendleton. For the rest of his life, the elder Samuel Maverick cautioned his children to always live in a healthful climate so that they would not fall victim to a tropical disease.

While in Charleston, the elder Samuel had operated a successful business importing goods from England, the Netherlands, Germany, Cuba, and France. After moving to Pendleton he gradually withdrew from his Charleston-based ventures and began to operate a small business in Pendleton. In 1814, the Maverick family expanded with the birth of another daughter, Lydia. Four years later, when Maverick was fifteen, his mother died.

It is likely that Maverick's early education took place at home. In early 1822, he traveled to Ripton, Connecticut, to study under a tutor. In September of that year he was admitted to Yale University as a sophomore. At Yale, he was known as "Sam". After graduating in 1825, Maverick returned to Pendleton and apprenticed under his father to learn business affairs. For the next year, his father deeded him land, and on February 4, 1826, he made his first land purchase, acquiring half a lot in Pendleton.

In 1828, Maverick traveled to Winchester, Virginia, to study law under Henry St. George Tucker, Sr. He became licensed to practice law in Virginia on March 26, 1829, and several weeks later he received his license to practice in South Carolina. He soon established a law practice in Pendleton. The following year he ran for a seat in the South Carolina legislature, advocating for a peaceful resolution to the tariff problem and against nullification. This was not a popular strategy, and Maverick placed 9th out of 13 candidates, gathering 1,628 votes.

Maverick relocated to Georgia in early 1833, where he unsuccessfully ran a gold mine. He returned home at the end of the year. On January 24, 1834, he left Pendleton for Lauderdale County, Alabama, taking 25 of his father's slaves to operate a plantation his father had given him. They arrived in March. Later that year his widowed sister, Mary Elizabeth, moved to Alabama to live near him with her three children. Maverick did not enjoy running a plantation, primarily because he did not like supervising slaves. On March 16, 1835, he left Alabama to go to Texas.

Maverick took the brig Henry from New Orleans and arrived at Velasco, at the mouth of the Brazos River, in April 1835. His interest in Texas extended back almost ten years, as in 1826 he noted in his journal that Stephen F. Austin had received a land grant and that Mexico was quickly being settled. When he arrived, there were fewer than 30,000 people living in the territory, which was then part of Mexico. Maverick immediately set out to buy land, making his first purchase on May 20. To officially transfer the title, Maverick had to go to San Felipe, and he spent the next several months traveling up and down the Brazos River from San Felipe looking for more land to buy. After recovering from a bout of malaria, Maverick journeyed to the drier climate of San Antonio, which was surrounded by large swaths of unclaimed land. Fifteen days after arriving in San Antonio he began buying large tracts of land

At this time there was much political unrest in Texas, as the colonists did not trust Mexican president Antonio López de Santa Anna to abide by the promises that had been made in the Mexican Constitution of 1824. The Mexican government believed that the colonists were preparing to revolt and hand Texas to the United States. After having been held in a Mexican prison for over 18 months, a newly released Austin returned to Texas with stories of what he had seen in the Mexican capital, and on September 19, 1835, he issued a call to arms. The first shot of the Texas Revolution soon occurred at Gonzales. General Martín Perfecto de Cos, the commander of the Mexican army in San Antonio, was distrustful of the Anglos in the area, and on October 16 he placed a guard at the door of the home where Maverick was staying. Maverick, his host John Smith, and another boarder, A.C. Holmes, were forbidden to leave the city. The Texan army soon arrived and, by October 24, had initiated the Siege of Bexar. Maverick had long kept a diary, which provided a "generally faithful eyewitness record of the events" of the siege. During this time, Maverick and his fellow prisoners sent missives to the Texans with information about the occurrences within the city, with many of them going to his childhood friend Thomas Jefferson Rusk.