This paper examines the nature of confidence in relation to cognitive abilities, personality traits, and metacognition. Confidence was measured as it was expressed in answers to each test item during the administration of reading and listening sections of the TOEFL® iBT. The confidence scores were correlated with the accuracy scores from the TOEFL iBT, SAT®, high school grade point averages (HS-GPA), and several measures of personality and metacognition. The results indicate that confidence is a separate psychological trait, somewhere between cognitive ability and personality traits. In addition, our findings suggest that confidence is related to, but separate from, metacognition. We also demonstrated gender and ethnic differences in confidence, with male and African American students showing higher overconfidence bias than females and White or Hispanic students, respectively. Finally, our data show small but statistically significant incremental validity of the confidence scores above and beyond the accuracy scores in predicting numeracy test scores, the total TOEFL iBT scores, and TOEFL iBT subscores on the writing and speaking sections. We found no incremental validity of the confidence scores in predicting the SAT and HS-GPA. Theoretical and practical implications of these findings are discussed as well.