BackgroundFully online learning has become a common option in many universities worldwide in the post-COVID-19 era. The study aimed to evaluate the dimensions and characteristics of the fully online learning self-efficacy among Chinese undergraduate medical and nonmedical students.MethodsA cross-sectional study was conducted from January to August 2023 at Xihua University in China. A stratified cluster sampling method was used to enroll participants of undergraduate students. The Chinese version of the online learning self-efficacy scale (OLSES) was used to collect the demographic information. Cronbach’s alpha coefficient, exploratory factor analyses, confirmatory factor analyses, and linear regression analyses were conducted in the study.ResultsA total of 203 college students were included in the study. One hundred and twenty (59.1%) of the participants were medical students and 83 (40.9%) were nonmedical students, and most of them (64.5%) were from rural areas. The Cronbach’s alpha coefficients were determined to be 0.90, 0.86, 0.87, and 0.95 for the learning in a fully online environment, time management, technology use subscales, and the whole scale, respectively. Exploratory factor analysis revealed the justifiability of factor analysis. In the confirmatory factor analysis, the majority of the goodness-of-fit indices reached an acceptable threshold (χ2/df = 3.14, RMR = 0.06, RMSEA = 0.10, NFI = 0.84, RFI = 0.80, IFI = 0.89, TLI = 0.85, CFI = 0.90). More than half of the students reported insufficient self-efficacy for learning in a fully online environment and time management, whereas 55.7% showed good self-efficacy for technology use. Although more medical students than non-medical students had higher self-efficacy scores in the three domains of self-efficacy, the proportion of students with good self-efficacy was slightly lower among medical students than non-medical students, with no significant differences between the medical students and nonmedical students.ConclusionsMost Chinese university students’ that participated to our study found self-efficacy for fully online learning as insufficient (results on the three domains, ranging from 36.5 to 55.7%) and had a good level of fully online learning self-efficacy. Medical students and nonmedical students are not differences in the self-efficacy of fully online learning. Thus, pedagogues should take measures to help students including medical and nonmedical improve their self-efficacy in online environment learning, time management and technology use, ultimately enhancing their academic success.