The objectives of this thesis are to study the links and commonalities between the two concepts, in order to first answer the essential questions: can laïcity be sacred? and can the sacred be secular? Considering that spirituality itself can be considered as secular and not necessarily religious, this research therefore attempts this challenge of bringing the sacred closer to laïcity by betting that the sacred is not the sole prerogative of religion nor the monopoly of dogmas.After having defined the concepts and illustrated their field of investigation, the researcher offers a comparison of possible common points, examples of convergences in the different sectors of society: shared roots in ethics and morals, links with the Public School, ...