Objective: The purpose of this study is to assess the hearing knowledge, earphone usage patterns, and attitudes toward earphone use among adolescents, and to analyze the differences in hearing knowledge based on earphone usage patterns and attitudes. Methods: This study employed a descriptive research design, with participants consisting of first- and second-year students from two general high schools in G City. The collected data were analyzed using SPSS version 27 statistical software. Results: A total of 93.2% reported using personal audio devices, and the average hearing knowledge score was 3.67±1.06. Among the participants, 92.4% used earphones during online lectures, and the first use of earphones occurred during middle school for 40.2% and elementary school for 39.1%. Hearing knowledge was significantly higher when earphones were used in places such as libraries or study rooms (p=.002) and when the volume was lowered during use (p=.027). Conclusions: This study provides meaningful insights into adolescents' earphone usage patterns. It suggests the need for the development of hearing programs that include education on earphone usage locations, volume control, and hearing health.