Seventy-eight percent of respondents said they have a "great deal" or "quite a lot" of confidence in the military, results indicated.
A majority of those surveyed also said they held small business and the police in high regard.
Coming in last were big business, health maintenance and Congress.
Gallup has polled Americans about how much confidence they have in a number of U.S. institutions 35 times since 1973, including annual updates since 1993.
Little changed in confidence in institutions this year over last, the Princeton, N.J., polling agency said. The only notable difference was a significant increase in respondents' confidence in television news, up from last year's 22 percent to 27 percent this year.
Despite highly publicized battles between public employee unions and state governments over benefits and bargaining rights, confidence in organized labor did not change appreciably -- 20 percent in 2010 and 21 percent in 201, results indicated.
Results are based on nationwide telephone interviews conducted with 1,020 adults June 9-12, 2011. The margin of error is 4 percentage points.