"He was a great scientist and an extraordinary man whose work and legacy will live on for many years," his three children, Lucy, Robert and Tim, said in a joint statement.
Neil deGrasse Tyson, another scientist who has made great strides in popularizing the field among the wider public, paid tribute to the Cambridge academic with a typically tongue-in-cheek physics joke.
"His passing has left an intellectual vacuum in his wake," the astrophysicist wrote on Twitter.
NASA's official Twitter account marked his death with a moving tribute.
"Remembering Stephen Hawking, a renowned physicist and ambassador of science. His theories unlocked a universe of possibilities that we & the world are exploring," it said.
The European Space Agency wrote of how Hawking "showed us there are no limits to achieving our dreams" alongside a photograph of the physicist enjoying the weightlessness of a zero-gravity flight in 2007.
World and industry leaders also noted his passing. Indian Prime Minister Narendra Modi tweeted his condolences.
Former colleagues from the world of academia and research also posted memories of Hawking.
Egyptologist and "space archaeologist" Sarah Parcak recalled how one encounter between the two almost came to a messy end.
David Wands, director of the Institute of Cosmology and Gravitation at the University of Portsmouth in southern England and former student at Cambridge, recalled how crowds turned out to listen to Hawking lecture.
Martin Rees, emeritus professor of cosmology and astrophysics at the University of Cambridge, met Hawking when they were both students in 1964.
"Astronomers are used to large numbers. But few numbers could be a large as the odds I'd have given, back in 1964 when Stephen received his 'death sentence,' against witnessing this uniquely inspiring crescendo of achievement sustained for more than 50 years," Rees said. "Few, if any, of Einstein's successors have done more to deepen our insights into gravity, space and time.
"His name will live in the annals of science; millions have had their cosmic horizons widened by his best-selling books; and even more, around the world, have been inspired by a unique example of achievement against all the odds — a manifestation of amazing will power and determination," he added.
Stars across the globe also paid tribute to Hawking on Wednesday.
Hawking also made multiple appearances guest-starring as himself on the top-rated US nerd comedy "The Big Bang Theory," which posted a snap of the beloved physicist surrounded by the cast.
Huffington Post reporter Ashley Feinberg also recalled his sense of humor.
"One of my favorite things about Stephen Hawking is that he was mean to all the right people," she posted, along with text recounting how he would "enjoy running over the toes of people he didn't like" with his wheelchair, including an anecdote of allegedly doing exactly that to Prince Charles.
Tanya Harrison, "professional Martian" and director of research at Arizona State University's Space Technology and Science Initiative, recalled what an inspiration Hawking was to her growing up, especially given his disability — he suffered from amyotrophic lateral sclerosis for more than five decades.
The Planetary Society, referencing a famous quote from popular astrophysicist Carl Sagan, posted a photo of Hawking alongside society members. "Goodbye, Dr. Hawking. Thank you for sharing your beautiful mind with this pale blue dot," it said.