The purpose of this study was to identify the correlation between depression, anxiety, e-health literacy (eHL), and health-promoting behaviors among nursing students during the coronavirus disease 2019 (COVID-19) pandemic, and to identify the factors affecting health-promoting behaviors. A cross-sectional study was conducted online, recruiting 301 nursing students recruited from 4 universities in the Chungcheng Province and Daejeon Metropolitan City in South Korea between May 28 and June 30, 2021. Data were analyzed using SPSS WIN 27.0. The general characteristics of the study participants were analyzed by frequency and percentage, and the degree of depression, anxiety, eHL, and health-promoting behaviors were calculated as averages and standard deviations. Differences in health-promoting behaviors according to general characteristics were analyzed using independent t tests and analysis of variance, and a post hoc Scheffe test was conducted. Correlations between depression, anxiety, eHL, and health-promoting behaviors were measured using Pearson correlation matrices. Stepwise multiple regression was performed to identify factors affecting health-promoting behaviors. During the COVID-19 pandemic, the average level of depression and anxiety was reported to be 3.93 (4.71) and 3.40 (4.30), respectively; 33.2% of nursing students experienced more than mild depression and 29.2% experienced anxiety. The average eHL level was 3.91 (0.56), and the average of health-promoting behaviors was 2.43 (0.45). Depression was positively correlated with anxiety (R = 0.734, P < .001) and negatively correlated with health-promoting behaviors (r = -0.198, P = .001), whereas eHL had a positive correlation with health-promoting behaviors (R = 0.347, P < .001). The factors affecting health-promoting behaviors were religion (β = -0.160, standard error [SE] = 0.048), current health status (β = -0.097, SE = 0.032), frequency of searching the Internet for health-related information in a week (β = -0.070, SE = 0.026), interest in health (β = -0.191, SE = 0.039), and critical eHL (β = 0.243, SE = 0.040); the explanatory power was 27.4%. Results demonstrate that during the COVID-19 pandemic, higher depression and anxiety among nursing students decreased health-promoting behaviors, while higher eHL increased health-promoting behaviors, and eHL was a major factor affecting health-promoting behaviors. These results contribute to the provision of basic data for the development of nursing intervention programs and educational strategies that can establish correct health-promoting behaviors by managing depression and anxiety among nursing students and improving eHL.