“…Lesson study is called both "ders araştırması" and "ders imecesi" in Turkish literature (Baki, 2012;Baki, Erkan, & Demir, 2012). There is many different research about lesson study in Turkey (Akbaba- Dağ & Doğan-Temur, 2018;Baki, 2012;Baki & Arslan, 2014;Baki et al, 2012;Bayram & Bıkmaz, 2019;Bilge & Dede, 2020;Boran & Tarım, 2018;Budak et al, 2011;Bütün, 2015;Dağ, 2014;Eraslan, 2008;Erbilgin, 2013;Güner & Akyüz, 2017;Güner & Akyüz, 2020;Jacobs, 2012;Kıncal & Beypınar, 2015;Serbest, 2014). TIMSS (the trends in international mathematicsh and science study) has compared 4th grade and 8the grade students' achievements in mathematics and science internationally since 1995 in Turkey.…”