Tymoshenko is serving a seven-year prison sentence after being convicted on charges she abused her authority when in 2009, while serving as prime minister, she helped broker a natural gas deal with Russia's Gazprom.
"The people of Ukraine demand democracy, and judicial transparency is the first place to start," said Inhofe in a statement. "Our unwavering support is with Ms. Tymoshenko and political prisoners everywhere."
The Senate measure calls for a visa ban against Ukrainian President Viktor Yanukovych and urges transparency in upcoming parliamentary elections in October.
Tymoshenko lost a bitter campaign for president to Yanukovych during the 2010 race. Her supporters say the charges against her are politically motivated.
"The Senate sent a firm message to Ukraine that their political persecution tactics of imprisonment and intimidation have no place in democracy," said Inhofe.