A study being released Thursday compared every state, the District of Columbia and Defense Department schools against 38 countries and nine additional subnational education systems.
Researchers took eighth-grade test results in math and science from the 2011 National Assessment of Educational Progress to predict performance on the Trends in International Mathematics and Science Study.
Tennessee scored 524 in science, but got a 490 in math, one of three states that scored below the international average of 500 in that category.
Data earlier showed Tennessee's high school graduates fell short of national results for ACT college readiness benchmarks this year.
The biggest gap was in math, with 29 percent deemed college ready, compared with 44 percent nationwide.