Out-of-school learning may include structured learning experiences that occur in school spaces after school hours or outside the classroom (Kendall et al., Education outside the classroom: Research to identify what training is offered by initial teacher training institutions. DfES, 2006). This chapter presents an overview of such school-based out-of-classroom learning environments and opportunities. Related learning opportunities in school spaces may include activities such as family math nights (Thanheiser, International Journal of Mathematical Education in Science and Technology, 51(7), 1059–1087, 2020), bake sales for the benefit of the school (Usta et al., Yaşadıkça Eğitim, 37(3), 711–733, 2023), and World Mathematics Day celebrations featuring various mathematics activities (Kurtuluş, Eğitim ve Öğretim Araştırmaları Dergisi, 4(1), 107–116, 2015) etc. I provide many more examples in the chapter. Such activities can take place in diverse locations within the school campus, such as the school garden, library, gymnasium, school corridors, or laboratory (Çağlar et al., Mehmet Akif Ersoy Üniversitesi Sosyal Bilimler Enstitüsü Dergisi, 10(23), 11–26, 2018; Malkoç & Kaya, Elementary Education Online, 14(3), 1079–1095, 2015). However, the effectiveness of most of the practices discussed in this chapter is still open to debate, regardless of how often they are implemented in schools. Therefore, further empirical studies are recommended to examine the advantages and disadvantages of school-based out-of-classroom practices for mathematics education.