This study explores the effect of an explicit training module on improving language learner ability to accurately self-assess second-language proficiency. There was a total of 409 intermediate and advanced level participants across six languages: French, Italian, Japanese, Portuguese, Russian and Spanish. Most of the participants had extensive immersion backgrounds. The Language Ability Self Evaluation Resource (LASER) was used to measure the perceived proficiency of the participants (self-assessed language ability). The Oral Proficiency Interview – Computer (OPIc) was used to measure the actual proficiency of the participants (rater-assessed language ability). The participants were randomly assigned to either the control or experimental group. Both groups started and ended the self-assessment the same way, with the experimental group receiving the training directly before the self-assessment questions. The training module was designed to include clarification, instruction, modeling, practice and immediate feedback while only adding 10 minutes to the overall assessment time. The limited time was dictated by the overall desire for maximum usability within already busy curricula and by already busy students. All participants completed the OPIc within 30 days of taking the LASER. The results were unexpected, revealing that those learners who received the training were more likely to over-assess their own proficiency level than learners who received no training at all. Possible reasons for this outcome are explored and possible ways to improve the assessment tool are discussed.