WASHINGTON — A federal judge handed a crucial free-speech victory to six University of Florida professors Friday, ordering the university to stop enforcing a policy that had barred them from giving expert testimony in lawsuits against the state.

The stinging ruling, by Judge Mark E. Walker of U.S. District Court for the Northern District of Florida, accused the university of trying to silence the professors for fear that their testimony would anger state officials and legislators who control the school’s funding. Judge Walker likened that to the decision last month by Hong Kong University to remove a 25-foot sculpture marking the 1989 massacre of student protesters in Beijing’s Tiananmen Square by the Chinese military, apparently for fear of riling the authoritarian Chinese government.