There are many ICT tools that teachers can use to support teaching and learning. In recent years, Learning Management Systems (LMSs) have been present in most higher education institutions. However, the availability of LMSs in K-12 is more recent. Furthermore, we believe that LMSs are promising even for K-12 teachers in face-to-face learning contexts because they have many educational features that can support learning with students. The goal of this study is (1) to identify the factors that influence the acceptability of the LMS by teachers, (2) to see if teachers' ICT use influences their intention to use the LMS, and finally (3) to see if teachers' ICT use influences their perception of the affordances of LMS educational features. The LMS in our study was introduced in a school board of more than 35,000 students and approximately 2400 teachers. To study the acceptability of the LMS, we used the Technology Acceptance Model. The results obtained from the show that the perception of usefulness is a good predictor of the intent to use the LMS. As for ICT use and the affordances of LMS educational features, the results show that they are not a good predictor of the intention to use.