1 Citation: Greenhow, C. & Askari, E. (in press). Learning and teaching with social network sites: A decade of research in K-12 related education. Education and Information Technologies. Learning and teaching with social network sites: A decade of research in K-12 related education Christine Greenhow Michigan State University greenhow@msu.edu Emilia Askari Michigan State University askariem@msu.edu Abstract The increasingly widespread use of social network sites to expand and deepen one’s social connections is a relatively new but potentially important phenomenon that has implications for teaching and learning and teacher education in the 21 st century. This paper surveys the educational research literature to examine how social network sites are perceived and used by K-12 learners and teachers with what impacts on pedagogy or students’ learning. Five themes were evident in the reviewed studies (n=24); the studies focused on: students’ informal learning outside of school; students’ formal learning in schools and classrooms; connections between in- and out-of-school learning; preservice teachers’ perceptions and practices and inservice teachers’ perceptions and practices. Furthermore, selected studies were summarized and categorized according to the four types introduced by Roblyer (2005) as studies most needed to move the educational technology field forward. These include studies that establish the technology’s effectiveness at improving student learning; investigate implementation strategies; monitor social impact; and report on common uses to shape the direction of the field. The most prevalent type of study conducted was research on common uses. The least common type of study conducted was research that established the technology’s effectiveness at improving student learning. Implications for the design of future research and teacher education initiatives are discussed. Keywords Social media, social network sites, teaching, learning, teacher education