This study examined the construct validity of the TOEFL iBT Speaking subsection for the purposes of international teaching assistant (ITA) certification, a purpose for which it was not specifically designed. The factor structure of the new TOEFL was compared with that of another language performance test in use at a major American research university for ITA certification. A quantitative, confirmatory factor analytic approach used data from 85 participants to analyze the extent to which the two tests measured the same constructs and to what extent some particular aspects of communicative language ability were measured by the new TOEFL Speaking test. Results suggest that the new TOEFL Speaking test measures the same general speaking proficiency construct, to a large degree, as the test designed specifically for teaching assistant screening. Implications for ITA testing programs and future validation work are discussed.