The goal of this thesis is to develop an ontology-based system for recommending digital educational games that take into account the individual educational needs of students with intellectual disabilities. The system is developed as a support for special education teachers in improving the educational process. To achieve the main goal, several preliminary studies were conducted to create the system. First, a systematic review of the literature on the use of digital educational games was conducted. This identified which technologies and games are used to achieve learning based on digital educational games for students with intellectual disabilities, and for which skills, abilities, and subjects the games are developed. Then, a systematic literature review on the use of ontologies in education was conducted. This identified different types of ontologies, approaches to their development, and the growing trend towards the popularity of multiple ontologies, which was useful in the development of the system as it contains multiple ontologies - to describe the domain of learning, more specifically the domain of digital educational games, and to describe data about students. For the purpose of creating the prototype for recommending digital educational games, a framework for evaluating digital educational games for students with intellectual disabilities was created. The framework identifies key characteristics of students with intellectual disabilities that are used to gain insight into the student's abilities, but also a set of characteristics of digital educational games that describe the requirements and functionalities of games, with the goal of determining whether a particular game is appropriate for an individual student’s learning process. Thus, the framework for evaluating digital educational games for students with intellectual disabilities is based on the scale for evaluating skills in using digital educational games for students with intellectual disabilities, which was created using the Delphi method, and the original categorization of the requirements and functionalities of digital educational games, which was obtained through a systematic literature review. The mentioned framework is implemented as a multiple ontology. On this basis, the rules for proposing digital educational games that take into account the individual needs of students with intellectual disabilities were created. In accordance with the defined rules, two algorithms were developed, one that proposes digital educational games and defines the related educational objectives for the academic skills domain, and the other that proposes digital educational games for the everyday skills domain. Validation of the algorithms was performed by experts in the field of special education. The validation results showed that the digital educational games proposed by the system meet the individual educational needs of students with intellectual disabilities. The validation of the whole system was performed using an information system success testing model and structural modelling techniques to verify the relationship between the constructs of the specified model, to determine the adequacy of the model, and to evaluate the psychometric properties of the model, which included testing the composite reliability and convergent validity. The results of the system validation showed that special education teachers can successfully integrate digital educational games into the educational process of students with intellectual disabilities by using the system.