The research carried out for this doctoral thesis elucidated the relationship between factors of e-learning competencies and other factors on the one hand and acceptance of e-learning and the degree of its application in hybrid teaching practices of higher education teachers on the other, and determines the factors responsible for the differences between those higher education teachers who do and those who do not use e-learning technologies. On the basis of the studied literature, theories and models of competencies, and theories and models of acceptance of technology and innovation, we determined and defined the factors of e-learning competencies of higher education teachers and the factors of acceptance of such learning, as well as the basic, higher and advanced levels of e-learning application in hybrid teaching practices.The data for this thesis were collected from two groups of higher education teachers: those who did use e-learning (N=270) in hybrid teaching and those who did not use e-learning (N=271) in hybrid teaching. It was established that there is a difference between the users and the non-users of e-learning, the biggest difference being in attitudes toward the use of technology for e-learning. As regards the level of application of e-learning in a hybrid learning environment, it was found that higher education teachers who perceived ease of use of technology in teaching but lack pedagogical competence to use ICT in e-learning and a positive attitude toward the use of tecnology for e-learning applied e-learning only at the basic level. The higher level of e-learning was applied in hybrid teaching by teachers who do have the pedagogical competence to use ICT u e-learning and a positive attitude toward the use of technology for e-learning, who love to experiment with new technologies in teaching. Finally, it was found that e-learning was applied at the advanced level by those teachers who have higher levels of pedagogical competence to use ICT in e-learning, a more positive attitude toward the use of technology for e-learning, are more willing to experiment with the possibilities of application of new technologies in teaching, and enjoy technical and pedagogical support from their university and/or their home institution for application of e-learning in the hybrid form of instruction.The results of this study were used to create a conceptual model that explains the model of acceptance of technologies for e-learning in higher education institutions in Croatia. We believe that the research carried out in this doctoral thesis has yielded good results which can be used to improve the scope and degree of e-learning in a hybrid learning environment, and which are applicable to other higher education institutions in Europe and worldwide.