Critical thinking is an essential competency for vocational students, yet the rapid adoption of artificial intelligence in learning may erode it when it is not balanced by adequate self-belief. This study aims to analyze the effect of Artificial Intelligence (AI) use and self-efficacy on the critical thinking skills of Office Management and Business Services (MPLB) students at SMK Mahardhika Surabaya, both partially and simultaneously. A quantitative approach with an explanatory research design was employed. From a population of 252 students, a sample of 155 was drawn using the Slovin formula through a proportionate stratified random sampling technique. Data were collected through Likert-scale questionnaires and analyzed using Partial Least Squares–Structural Equation Modeling (PLS-SEM) with SmartPLS version 4.0. The results show that: (1) AI use has a positive and significant effect on critical thinking, although its contribution is relatively weak; (2) self-efficacy has a positive and significant effect and is the most dominant factor; and (3) both variables simultaneously have a significant effect, explaining 53.6% of the variance in students' critical thinking, while the remaining 46.4% is attributable to other variables outside the model. These findings indicate that students' critical thinking is determined more by self-belief than by the use of AI technology, so that strengthening self-efficacy needs to be accompanied by the wise and reflective use of AI. Students are encouraged to cultivate self-efficacy and use AI reflectively, and future research is advised to add other variables and focus on specific subjects.