The dataset comprises questionnaire responses collected from Slovenian lower-secondary science teachers who teach science in the 6th and 7th grades (students aged 11–12). The questionnaire captured multiple dimensions related to outdoor science education, including teachers’ attitudes toward teaching science outdoors, self-reported use of outdoor instructional practices, professional development experiences, nature connectedness and nature relatedness, self-efficacy for outdoor teaching, and perceived challenges and constraints associated with outdoor science education. Additional items addressed contextual and demographic characteristics relevant to teaching practice. The dataset provides a comprehensive overview of teacher-level factors shaping the implementation of outdoor science education in compulsory schooling.