Digitization, increasing heterogeneity among students, or restrictions due to the Covid-19 pandemic: Dealing with changing demands, and thus acting proactively, is essential for nowadays’ teachers. Inter-individual differences in teachers’ self-starting, future- and change-oriented behavior (proactive behavior) contribute to the success of everyday practice at school as well as to innovations and future quality. Still, inter-individual differences regarding those behaviors are a little studied topic in educational psychology. This study aims to introduce and evaluate instruments to assess teachers’ proactive behavior systematically and theory-based: First, we evaluate our adaptations of three established self-report scales for proactive behavior that have been adjusted to capture relevant behavior in teaching profession. Additionally, we address the call for behavior measurment, that captures constructs closer to actual behavior, by the introduction and evaluation of a newly developed behavior checklist for teachers’ proactive behavior. Entweder: In two independent samples of German teachers we investigate our instruments in terms of reliability (McDonalds’ Omega or retest), internal validity (model fit, exploratory and confirmatory factor analysis), as well as construct validity by the means of convergent and divergent relations between the instruments and with established scales (latent correlations).