The level of learner satisfaction, according to Chen and Yao (J Educ Res 4(7):1667-1671, 2016), has a main role in measuring the effectiveness of blended learning, which is influenced by various factors. The purpose of this study was thus twofold: (a) to explore graduate students' attitudes, interaction patterns, and satisfaction with blended learning technology and (b) to investigate the extent to which attitude, interaction, and quality of teaching contributed to satisfaction. The participants of this study were 140 graduate students of TEFL at the e-learning campus of Iran University of Science and Technology. The instruments were four types of questionnaire on learner satisfaction, attitude, interaction types, and quality of teaching. The results of quantitative and qualitative analysis revealed learners' positive attitudes towards blended learning technology. The instructor was also successful in teaching theoretical and practical concepts of TEFL, guiding online discussion through giving constructive feedback, and motivating learners to do more online learning. Learner-instructor interaction was also found to be the most frequent type of interaction. The results of multiple regression analysis also revealed that contribution of quality of teaching to satisfaction was higher than that of interaction and attitude, implying the significance of training online teachers to enhance their knowledge, skills, and strategies required for online teaching.