The data makes it the second-lowest ratings for the Tony awards since 1988.
The Tony broadcast was up against the season finale of AMC's "Mad Men" but faced no competition from the NBA postseason, as it did last year when it aired opposite Game 6 of the NBA Finals.
Neil Patrick Harris returned as host again this year but there was no clear, dying-to-see-it front-running Broadway show like last year's juggernaut, "The Book of Mormon." The sweet musical "Once" won eight awards this year.
Updated ratings figures will be available on Tuesday.