Despite widespread efforts to promote Open Educational Resources (OER) in German K-12 education, their adoption remains relatively low. Previous research has identified common enablers and barriers to OER adoption (i.e., OER (re)use, adaptation, and creation) from an international and intercultural perspective while a hierarchy of such predictors has not been established yet. In order to inform future support structures and policies, this study aimed to identify the most important enablers and barriers to OER adoption in German K-12 education. For this purpose, common enablers and barriers as well as survey items covering these were identified through a literature review. 1,639 teachers were surveyed. While the tested models for whether and how often educators reuse or create OER showed significance, their predictive power was limited. Notably, awareness of OER, and the frequency of cooperation and local sharing of educational resources were the strongest and most consistent predictors. Other predictors such as lack of high-quality material, lack of time, attitude towards sharing, and OER-related skills were less consistent or showed little explanatory power. In conclusion, commonly identified enablers and barriers alone cannot fully explain OER adoption patterns in this context. These findings highlight the need for more context-specific approaches to enhance OER integration which in turn could inspire OER promotion in similar contexts.