Harris Interactive surveyed 2,240 adults online May 8-13.
Tennant and Baker each garnered 16 percent among those who had ever watched the show.
Coming in at No. 3 is the current and outgoing Doctor, Matt Smith, with 7 percent of the vote.
Patrick Troughton is No. 4 with 5 percent, Peter Davison is No. 5 with 4 percent, Christopher Eccleston and Colin Baker each earned 3 percent.
Twenty-seven percent of hardcore "Doctor Who" fans said Tennant is their favorite star.
Baker is second with 24 percent of the vote and Smith is No. 3 with 10 percent.
The BBC announced Sunday Peter Capaldi will replace Smith and become the 12th Doctor Who on the long-running series.