Aaron Hillel Swartz (November 8, 1986 – January 11, 2013) was an American computer programmer, entrepreneur, writer, political organizer, and Internet hacktivist. He was involved in the development of the web feed format RSS and the Markdown publishing format, the organization Creative Commons, the website framework web.py, and the social news site Reddit, in which he became a partner after its merger with his company, Infogami. Swartz's work also focused on civic awareness and activism. He helped launch the Progressive Change Campaign Committee in 2009 to learn more about effective online activism. In 2010, he became a research fellow at Harvard University's Safra Research Lab on Institutional Corruption, directed by Lawrence Lessig. He founded the online group Demand Progress, known for its campaign against the Stop Online Piracy Act. On January 6, 2011, Swartz was arrested by MIT police on state breaking-and-entering charges, after connecting a computer to the MIT network in an unmarked and unlocked closet, and setting it to download academic journal articles systematically from JSTOR using a guest user account issued to him by MIT. Federal prosecutors later charged him with two counts of wire fraud and eleven violations of the Computer Fraud and Abuse Act, carrying a cumulative maximum penalty of $1 million in fines, 35 years in prison, asset forfeiture, restitution, and supervised release. He committed suicide while under federal indictment for his alleged computer crimes. Swartz declined a plea bargain under which he would have served six months in federal prison. Two days after the prosecution rejected a counter-offer by Swartz, he was found dead in his Brooklyn apartment, where he had hanged himself. In August 2013, Swartz was inducted posthumously into the Internet Hall of Fame.

He is also known as Swartz, Aaron, Aaron H. Swartz, AaronSw, Aaron Hillel Swartz and Aaron Hillel George Swartz.

On the evening of January 11, 2013, Swartz was found dead in his Brooklyn apartment by his partner, Taren Stinebrickner-Kauffman. A spokeswoman for New York's Medical Examiner reported that he had hanged himself. No suicide note was found. Swartz's family and his partner created a memorial website on which they issued a statement, saying: "He used his prodigious skills as a programmer and technologist not to enrich himself but to make the Internet and the world a fairer, better place."

Days before Swartz's funeral, Lawrence Lessig eulogized his friend and sometime client in an essay, Prosecutor as Bully. He decried the disproportionality of Swartz's prosecution and said, "The question this government needs to answer is why it was so necessary that Aaron Swartz be labeled a 'felon'. For in the 18 months of negotiations, that was what he was not willing to accept." Cory Doctorow wrote, "Aaron had an unbeatable combination of political insight, technical skill, and intelligence about people and issues. I think he could have revolutionized American (and worldwide) politics. His legacy may still yet do so."