Through the Blended Learning model, this study explores the factors affecting fostering of information and communications technology (ICT) applications in teaching for teachers in the Northern midland and mountainous provinces of Vietnam. The survey is designed to be uploaded to the Learning Management System (LMS) system and requires learners to answer online after completing the course. Influential factors are considered, including 9 groups formed from 45 questions (independent variables). The independent variables are evaluated based on the 5-level Likert score bar. This study uses Cronbach's alpha to determine the reliability of the questions. The survey received responses from 1484 teachers who completed the course in the northern midland and mountainous provinces. After removing the answers with no statistical significance, the remaining samples included in the analysis through SPSS software were 558. The results of the EFA analysis retain 29 observed variables and indicate 7 factors affecting the fostering of ICT application in teaching for teachers. Next, using CFA (Confirmatory Factor Analysis), the study removed 02 more observed variables and pointed out 7 factors affecting the effectiveness of fostering information technology application in teaching for teachers, includes (i) Training methods; (ii) Organization of training courses; (iii) Online learning management system; (iv) Facilities for face-to-face learning; (v) Training content; (vi) Training objectives; (vii) Impact of training content. The results will help researchers and educational administrators find ways to improve the quality of professional development for teachers in high schools in this content and other similar contents.