Terms of the deal were not disclosed for Williams, who played in just three games over the last two seasons with the Atlanta Falcons.
Williams, 27, has 28 receptions for 263 yards and two touchdowns in 22 career games with the Washington Redskins and Falcons.
The 5-foot-10, 184-pound Williams joins former Baltimore Ravens wideout Michael Campanaro as free-agent additions to the receiving corps in Tennessee. Corey Davis, Taywan Taylor, Tajae Sharpe and Rishard Matthews are also on the wide receiver depth chart for the Titans.
Williams will also be reunited with Matt LaFleur, the Titans offensive coordinator who served as quarterbacks coach with the Falcons in 2015-16.