Texts and instructional pictures are widely used for facilitating students' understanding of complex content, especially in science subjects. International large-scale assessments repeatedly reveal differences in students' science achievement between countries. Since text-picture material (TPM) plays an essential role in science education, it is reasonable to investigate TPM-related distinguishing characteristics. In general, teachers need professional competences such as attitudes, motivational orientations, and self-regulatory skills for supporting student learning. It is plausible to assume that this also applies for teaching and learning with TPM. This article reports on comparisons of (a) Omani and German science teachers (country comparison), and (b) German science and language teachers (domain comparison). In a cross-sectional design, data was collected from 450 secondary school teachers. Structural equation models revealed country-specific and domain-specific differences in teachers' TPM-competences. This study contributes to the body of research on teacher professionalism in different cultural settings, providing implications for teacher education.