<p>This study investigated the efficacy of a web-based self-help platform, developed on cognitive-behavioral principles, in reducing test anxiety among college students from Turkey and the USA. Additionally, it aimed to elucidate cultural differences in test anxiety levels and the platform’s effectiveness. The study comprised 290 college students, with equal representation from Turkey (<i>n</i> = 145) and the USA (<i>n</i> = 145). The Westside Test Anxiety Scale was administered as both a pre-test and post-test measure. Data analysis employed independent samples <i>t</i>-tests, Pearson product-moment correlation coefficients, dependent samples <i>t</i>-tests, and Wilcoxon signed-rank tests. In the US sample, gender and age were significantly correlated with test anxiety levels, with female and younger students exhibiting higher test anxiety. Conversely, the Turkish sample showed no significant gender differences or age correlations in test anxiety levels. In summary, the results substantiated the platform’s effectiveness in mitigating test anxiety for students from both countries. Furthermore, the study revealed both similarities and differences in cultural aspects of test anxiety and the platform’s efficacy between the two countries. It was determined that the self-help platform developed based on the cognitive-behavioral approach could be used in counseling by proving its effectiveness in both countries.</p>