 This research aims to fill a cloud-based learning environment of secondary school with multimedia content using authoring tools and H5P. It analyzes state standards, statistics and pedagogical experience and publications, as well as experimentally applies the H5P tool to create multimedia content based on HTML5. This research also examines existing content management systems to replicate materials and uses H5P to create up to 20 types of independent multimedia content compatible with a full range of web browsers and devices with touch interface support. As a result, this research provides a means to create, share and reuse content in an HTML5 format for cloud-based learning environment of secondary school, offering many opportunities to study learning material and assessment of pupils. Additionally, the results of this research will be generalized to form recommendations for filling multimedia content of the cloud-based learning environment of secondary school. This article was authored by A.V. Vorisbit.