Thomas Jefferson Hogg (24 May 1792 – 27 August 1862) was a British barrister and writer best known for his friendship with the Romantic poet Percy Bysshe Shelley. Hogg was raised in County Durham, but spent most of his life in London. He and Shelley became friends while studying at University College, Oxford, and remained close until Shelley's death. During their time at Oxford they collaborated on several literary projects, culminating in their joint expulsion following the publication of an essay titled "The Necessity of Atheism". They remained good friends, but their relationship was sometimes strained because of Hogg's attraction to the women who were romantically involved with Shelley.

Hogg became a barrister and met Jane Williams, who had become a close friend of Percy Shelley's shortly before the poet's death. Jane became Hogg's common-law wife and they had two children together. The family settled in London, although Hogg's legal career meant that he often had to travel away from home.

While living in London Hogg made the acquaintance of several well-known writers, and he published literary works of his own. He studied Greek literature for much of his life and published several articles on the subject, including two entries in the Encyclopædia Britannica. Most of the fiction he wrote was poorly reviewed. His best-known literary work was The Life of Percy Bysshe Shelley, an unfinished biography of the poet. Although the book was well researched and painted a clear picture of Shelley as a young man, it was criticised for portraying him negatively.

Hogg was well connected with Whig politicians. He received an appointment to a government commission on municipal corporations and became a revising barrister. His legal career was moderately successful, but he was often frustrated by his failure to attain his goal of becoming a professor or judge. Nevertheless, he was able to provide for his family thanks to an inheritance and the income from his legal career.