This scientific article is devoted to the systematic analysis of the theoretical-methodological foundations and practical principles of designing software aimed at developing 21st-century skills in the educational process of academic lyceums. In the research, taking into account the specific features of academic lyceums — a high level of requirements, short-term education, and the need to harmonize fundamental and practical knowledge — the requirements for software tools that serve to develop 21st-century skills (4K model: collaboration, communication, creative thinking, critical thinking) were developed. The article highlights design principles such as user-orientation, modularity, adaptability, interactivity, multifunctionality, continuity, security, integration, and didactic justification. Also, based on the experience of the Karlsruhe Institute of Technology (KIT), the concept of creating social learning platforms, user-centered design, and co-design methods were analyzed. At the end of the article, practical recommendations were developed for the introduction of software aimed at 21st-century skills for academic lyceums in Uzbekistan.