<p>This systematic literature review evaluates empirical research articles published after 2017 on emerging themes into outdoor science teaching, with a specific focus on in-service science teachers. Guided by two main research questions, we investigated the following: (1) What are the emerging themes into outdoor science teaching from the view of in-service teachers? (2) What are the directions for the further development of outdoor science education? Sixteen of the 609 potential articles from the Scopus and Web of Science databases met our selection criteria. Most of them are qualitative and span different regions of the world. Six interrelated themes reflecting the focus of the studies were identified: teaching practice, knowledge and skills, acknowledging benefits, acknowledging challenges, teacher awareness, and support. Future directions for outdoor science education were categorized into the following sections: implications for further research, outdoor practice, and curriculum recommendations. We conclude that a collaborative approach and commitment from teachers, school leaders, researchers, and policy makers is critical to further develop outdoor science education.</p>