This study has two aspects: the principal aim is to remember again and to conceptualise the most important principle of the founding elements of the Republic of Türkiye, laicism in Atatürk’s own mind in terms of his statements that appeared in his Speech (Nutuk) and Speeches and Statements (Söylev ve Demeçler). Secondly, it attempts to analyse the laic education as a tool in achieving the objective of modernisation in lights of Atatürk’s own reforms. In this context, the constitutional, legal and institutional developments during the 1919-1950 period are addressed in the first part of the book. A brief introduction on laicism and secularism follows the narration of modern and laic educational reforms starting from the late Ottoman period and the progress made in education during the Republican era. The main theme of the second part is the enterprises of modern, rational and laic educational understanding from “idea to action” under the leadership of Ankara in the process of development of modern, rational and laic education.