The problem and the aim of the study. The transformation of the educational space has identified as priorities for online teaching: improving the quality of the materials provided, supporting cognitive activity and students’ independence, preparing teachers for the active use of web technologies. To implement these requirements, the authors propose the use of cyber quests, which in a game form allow providing additional resources for formation of the foreign language communicative competence. Research methods. To obtain theoretical generalizations, the analysis of scientific works on the problem of gamification of learning, formation of cognitive activity and foreign-language communicative competence was used. The cyber quest was implemented in the Quandary software environment. The study involved 90 first-year students of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. The Pearson χ2 (chi-square) criterion was used in the experiment. Results. The essence of the concept «cyber quest», its functions and capabilities are investigated. The stages of developing cyber quests based on virtual worlds for learning a foreign language in the online format are defined. The mechanics of cyber quests in the Quandary program environment are described in detail (implementation options “Assembling the parts of the whole”; “Experience rating”; “Maintenance of an interactive object”; “Successive activation”). The cyber quest is focused on solving future professional problems in the direction of preparing “Agricultural Engineering” and includes two organization strategies: “Control” and “Training”. The main difficulties of software implementation (for example, the ambiguity of using open-type assignments) and methodological support (the need to maintain balance between the game and learning) are highlighted. The dynamics was assessed according to the levels of formation of the cognitive activity and statistically significant differences were revealed on the qualitative changes that occurred in the pedagogical system χ2obs. 2 > χ2crit.0.05 (6,70 > 5,99). In conclusion factors that ensure the effective use of the cyber quest to support the cognitive activity of students when learning a foreign language in the online format are summarized: non-linear motion paths; resolution of problematic situations of the practice-oriented nature; combination of entertaining and cognitive components, etc.