Organizations benefit from the use of training and performance assessments. Self-assessment is a way for trainees to monitor their progress throughout training and on the job. The literature indicates that ambiguity and skill level are factors that impact the accuracy of self-assessments. Previously, the effect of the interaction of ambiguity and skill level on self-assessment accuracy had not been investigated. The present study assessed the effect of skill level and item ambiguity on the accuracy of self-assessments made by Lieutenants and Captains in the U. S. Army. The results indicated that increased skill level resulted in increased accuracy of self-assessments while ambiguity had no effect. Counter to the hypothesis, as items became more ambiguous, both Captains and Lieutenants self-assessed more accurately. Implications and limitations are discussed, along with recommendations for future research.