Background: This study examined the factor structure of the Test of English for Academic Purposes (TEAP®) test--a recently developed academic English test measuring four skills among Japanese university applicants--and compared the structure to that of the Test of English as a Foreign Language Internet-based test (TOEFL iBT®), to investigate the extent towhich the TEAP test is related to the TOEFL iBT test. Methods: Using confirmatory item-level factor analysis and scores on both tests, obtained from 100 students, we tested four models (unitary, correlated, receptive-productive, andhigher-order) for the TEAP test. Results: We found that the higher-order model fit the data best. This suggests that the TEAP measures the four skills of reading, listening, writing, and speaking well and that they could be conceptualized as reflecting a single academic proficiency. This supports the appropriateness of the constructs, as defined and operationalized in the specifications of the TEAP test. Further, we found a close relationship between the TEAP and the TOEFL iBT tests (1.005). This suggests that both tests measure a very similar construct. This provides positive evidence of the concurrent validity of the TEAP test, as an indicator of academic English skills. These results were also supported by a follow-up analysis using item-parceled data. Conclusions: The close relationship between the TEAP and TOEFL iBT tests suggests that the TEAP test measures the intended construct of the four skills in academic settings very well.