This study determines the impact of a Learning Management System (LMS) called My English Lab (MEL) on student performance (SP) through academic motivation (ACM). Specifically, it identified factors affecting ACM when applying MEL. Meanwhile, it determined the relationship between SP and ACM. The research procedure consisted of 2 stages: Preliminary qualitative research was conducted to provide an appropriate framework to obtain the data needed for official quantitative study. The proposed model for the research included 3 independent variables namely Achievement (AM), Autonomy (AU) and Self-Efficacy (SE); the mediating variable ACM; and the dependent variable SP with 25 observed variables in total. The study used the mixed research approach combining qualitative and quantitative. Stratified Random Sampling was chosen for the Sample of the official research. The study was conducted within a 45-hour academic term. An online survey through Google form was carried out for 350 non- English- major first year students at Hanoi University of Business and Technology (HUBT). After checking Cronbach's Alpha for reliability and EFA for validity, the total number of observed variables included in the regression was 20. The statistical results showed R-2 approximate to 0.594, and R-2 approximate to 0.584 in regression and in PATH analysis respectively. The findings proved the three independent variables had positive impacts on ACM, in which AM is the greatest of the three. Also, the results revealed that there is a positive correlation between ACM and SP. Furthermore, after applying MEL, students' achievement test scores slightly improved. In the light of the findings, the author proposed that the Government of Vietnam should issue provisions and policies on the application of technology in teaching and learning, especially the use of LMS as an effective tool for students' self-study enhance ACM and SP enhance ACM and SP. Meanwhile, the study stated some limitations such as sample size, geographical location and time, and therefore, further studies were recommended.