Lantos, 80, died Monday of complications from esophageal cancer at Bethesda Naval Medical Center in Maryland.
"As the only Holocaust survivor ever elected to Congress, Tom Lantos devoted his life to shining a bright light on dark corners of oppression," said House Speaker Rep. Nancy Pelosi, a fellow Californian.
Bush called Lantos "a living reminder that we must never turn a blind eye to suffering of the innocent at the hands of evil men."
Bush said he appreciated Lantos' efforts to protect the environment, and his work on behalf of of HIV and AIDS patients and strengthen U.S. alliances around the world.
Senate Majority Leader Harry Reid, D-Nev., who once served with Lantos on the House Foreign Affairs Committee, said, "America benefited far more from Tom Lantos's service."
Rep. Mike Pence, R-Ind., ranking member of the Middle East and South Asia Subcommittee of the House Foreign Affairs Committee, said Lantos will be "sorely missed" in Congress.
"Tom Lantos was my sometime opponent but was, at all times, an inspiring friend," Pence said.