Both teachers' pedagogical and basic ICT competence beliefs are antecedents of ICT implementation in class. Research has developed instruments to assess teachers' pedagogical ICT competence beliefs. However, there is a paucity of research on the assessment of teachers' basic ICT competence beliefs. The purpose of this study was to develop and validate an instrument to assess teachers' basic ICT competence beliefs. Our analyses based on a sample of 372 teachers in Germany (51.2% women, age M = 44.48, SD = 10.77) who participated in an online survey. We used exploratory factor analyses to test the factorial structure and confirmatory factor analyses to investigate the multidimensionality of the measure. Construct validity was analyzed using teachers' attitudes toward ICT, ICT use, and socio-demographic variables as validation variables. Our analyses identified six dimensions of teachers' basic ICT competence beliefs: information and data literacy, communication and collaboration, digital content creation, safety and security, problem solving, and analyzing and reflecting. Three of these dimensions had a second-order structure. The six dimensions are differently correlated with teachers’ attitudes towards ICT, private and professional use of ICT, student-centered ICT teaching practices, and teacher gender. •Six dimensions of teachers' basic ICT competence beliefs were identified.•The theoretical assumed second-order structure can be seen for three competence dimensions.•Measurement invariance across gender and computer science as a subject can be established.•Basic ICT competence beliefs are correlated with ICT value beliefs and ICT use.•Enables investigations of different competence dimensions with ICT teaching strategies.