The paper presents the Open Educational Practices (OEP) initiative that was implemented in Greece, as part of the national strategy for digital educational content in primary and secondary education. It aimed at encouraging and motivating teachers to develop and share OEPs that draw upon the use and reuse of Open Educational Resources (OERs), found either at the Photodentro national content repositories for school education or elsewhere. A new Photodentro Repository for Open Educational Practices on resource-based learning was developed and used by teachers to host and share OEPs. A model structure and a template for describing OEPs, along with a set of quality criteria for OEPs are proposed. The country-wide action “i-participate”, supported by a network of regional ambassadors and a web portal, and the 1st Hellenic contest for best OEPs in K-12 education are also presented.