This research addresses three main purposes: 1) describing teachers’ preparation for EFL e-learning, 2) the implementation of Microsoft Teams for EFL e-learning, and 3) how is the EFL teacher’s evaluation of students’ achievement by using Microsoft Teams. By using qualitative research with case study, the researcher took a very special interest about the implementation of Microsoft Teams application as EFL e-learning media and LMS. The researcher studied about the case of Senior High School that is proven to have implemented this platform in a good way and became the first pioneer school in applying the e-learning media for teaching and learning activities. The subjects of this research were an EFL teacher and six EFL students. In this research, the data were collected through observation, interview, and documents. To achieve the three purposes of this research, the data were analyzed by five parallel flows activities including 1) organizing and preparing the data for analysis, 2) reading or looking at all the data, 3) coding all of the data, 4) using the coding process to generate a description of the setting or people as well as categories or themes for analysis, and 5) making an interpretation in qualitative research of the findings or result. Trustworthiness of the data such as credibility, transferability, dependability, and confirmability were used to validate the data. There are several findings showed in this research related to the research focus. First, in preparing EFL e-learning, the teacher of SMAN 2 Blitar created one-sheet lesson plan. Second, in implementing Microsoft Teams as EFL e-learning media, teacher shared material and assignment including the key answer on Teams before starting the class. Teacher combined Teams with conventional media such as book and whiteboard. Then, in pre-teaching, teacher focused on speaking skill training by conducting question answer session. By using Teams, students were more active in speaking. In while-teaching, it was focused on reading activity including vocabulary and grammar mastery. With Microsoft Teams, students were easier to understand the context, vocabulary, and grammar on the text. Meanwhile, the interaction between students and teacher through Teams, firstly, it came from school facility which provide special email for office 365 to access Teams. After users were able to access, they conducted discussion or asking question by using chat-box. While using this platform, several problems were confronted but teacher and students had responsibility to solve their problem, so that, the learning process could be done well. Even though there were several obstacles while using this platform, the users still impressed with the complete features of Teams that support the teaching learning process. Third, in evaluating students’ EFL e-learning, teacher gave assignment or test through Microsoft Teams including the key answer. Through Teams, teacher focused on assessing knowledge by giving essay assignment and multiple-choice question for test. The students’ attitudes and skills were assessed directly without using the app. In assessing knowledge by using Teams, it was much easier than the general offline class because teacher did not need to collect paper and do scoring manually. The Teams made automatic correction on students’ work. Suggestions based on the findings are directed at EFL teachers as well as other researchers in pursuing comparable subjects in future research. Those suggestions are in regards to technical writing and content. Moreover, this research can be utilized as a reference to make establishment of topics related to implementation of Microsoft Teams as EFL e-learning media such as the effectiveness of Microsoft Teams as EFL e-learning media.