46-year-old Williams along with two flight engineers -- Japan's Akihiko Hoshide and Yury Malenchenko of Russia -- departed on a two-day voyage to the International Space Station (ISS) aboard a Russian Soyuz spacecraft at around O8:10 IST, Russian news agency Ria Novosti reported.
Williams, a flight engineer on the station's Expedition 32 crew, will take over as commander of Expedition 33 on reaching the space station.
The Soyuz TMA is due to dock with the ISS's Zvezda service module at 10:22 IST on Tuesday.
The crew will join the current ISS occupants - Russian cosmonauts Gennady Padalka and Sergei Revin and NASA astronaut Joe Acaba, who have been in orbit since mid-May.
The new crew members are expected to conduct over 30 scientific missions during their stay on board the ISS.
Williams and Hoshide visited the ISS once each, traveling on board a US space shuttle. It is their first flight experience with the Soyuz spacecraft.
Williams, whose father hailed from Gujarat, was selected as an astronaut by NASA in 1998. She was assigned to the ISS as a member of Expedition 14 and then joined Expedition 15. She holds the record of the longest spaceflight (195 days) for female space travellers.
She received a Master's degree from the Florida Institute of Technology in 1995.
In the space, Williams and her team of astronauts plan an orbital sporting event to mark the Summer Olympics in London. PTI
NSA
