Gender differences in computer-related constructs have been identified for teachers and students. The present study investigated such differences by focusing on teachers’ computer self-efficacy (CSE), which is conceptualized as their confidence in performing basic and advanced skills in using computers, along with the use of computers for instructional purposes. Analyzing the data from 1208 Norwegian secondary school teachers who participated in the International Computer and Information Literacy Study (ICILS) 2013 by means of multi-group confirmatory factor analysis, we found that: (a) CSE can be described by three factors (self-efficacy in basic operational skills, advanced operational and collaborative skills, and in using computers for instructional purposes) which remain invariant across gender; (b) male teachers had higher CSE in basic (d = −1.03) and advanced operational skills (d = −0.49); (c) no significant gender differences for CSE in using computers for instructional purposes existed; (d) teachers’ CSE was differentially related to their participation in professional development courses for females and males. The differentiation into three factors of CSE provides a more detailed view on teachers’ CSE than unidimensional approaches. We discuss our findings in light of gender differences and teachers’ professional development in using information and communication technology.