In this study, we explored retest effects on test scores and response time for repeaters, examinees who retake an examination. We looked at two groups of repeaters: those who took the same form twice and those who took different forms on their two attempts for a certification and licensure test. Scores improved over the two test attempts, and repeaters taking the same form twice tended to have larger score gains than those taking different forms. This trend was more salient for female examinees than male and for White and Hispanic/Latino examinees than examinees from other ethnicity groups. In addition, over a third of the examinee responses were incorrect on the same form for both attempts, indicating that the knowledge required for these items was not addressed after these repeaters failed their initial attempt to answer those items correctly. Factors that may be related to these findings are discussed.