Professional vision of instructional support in primary science was investigated with respect to its content-specificity and to learning opportunities in initial teacher education (ITE) which are presumably relevant for the acquisition of this skill. Data from 196 primary pre-service teachers were used. Confirmatory factor analyses suggested pre-service teachers' professional vision of instructional support to be a content-specific skill rather than a general homogeneous or a content-independent one. MIMIC model results revealed that pre-service teachers’ general cognitive ability and the attendance of an ITE program with a focus on science were most significantly related to their professional vision of instructional support in science classes, whereas practical experiences were not.