Shenzhou 6 (Chinese: ; pinyin: Shnzhu luho) was the second human spaceflight of the Chinese space program, launched on October 12, 2005 on a Long March 2F rocket from the Jiuquan Satellite Launch Center. The Shenzhou spacecraft carried a crew of Fi Jnlng () and Ni Hishng () for five days in low Earth orbit. It launched three days before the second anniversary of China's first human spaceflight, Shenzhou 5.

The crew were able to change out of their new lighter space suits, conduct scientific experiments, and enter the orbital module for the first time, giving them access to toilet facilities. The exact activities of the crew were kept secret but were thought by some to include military reconnaissance, however this is likely untrue given that similar experiments in the US and USSR determined that humans in space are not suited for military reconnaissance. It landed in the Siziwang Banner of Inner Mongolia on October 16, 2005, the same site as the previous crewed and uncrewed Shenzhou flights.

Human spaceflight (also referred to as manned spaceflight or crewed spaceflight) is spaceflight with a crew or passengers aboard a spacecraft, often with the spacecraft being operated directly by the onboard human crew. Spacecraft can also be remotely operated from ground stations on Earth, or autonomously, without any direct human involvement. People trained for spaceflight are called astronauts (American or other), cosmonauts (Russian), or taikonauts (Chinese); and non-professionals are referred to as spaceflight participants or spacefarers.The first human in space was Soviet cosmonaut Yuri Gagarin, who launched on 12 April 1961 as part of the Soviet Union's Vostok program. This was towards the beginning of the Space Race. On 5 May 1961, Alan Shepard became the first American in space, as part of Project Mercury. Humans traveled to the Moon nine times between 1968 and 1972 as part of the United States' Apollo program, and have had a continuous presence in space for 21 years and 144 days on the International Space Station (ISS). As of 2021, humans have not traveled beyond low Earth orbit since the Apollo 17 lunar mission in December 1972.

Currently, the United States, Russia, and China are the only countries with public or commercial human spaceflight-capable programs. On 15 October 2003, the first Chinese taikonaut, Yang Liwei, went to space as part of Shenzhou 5. Non-governmental spaceflight companies have been working to develop human space programs of their own, e.g. for space tourism or commercial in-space research. The first private human spaceflight launch was a suborbital flight on SpaceShipOne on June 21, 2004. The first commercial orbital crew launch was by SpaceX in May 2020, transporting, under United States government contract, NASA astronauts to the ISS.