This presentation reports teacher development sessions invested education authority for more than 1400 secondary school English teachers involved in “Open Online Module Training” through the APLUS.mn education platform in Mongolia. The sessions were engaged with MERA & Lingors and Authority for Education to develop extensive reading in the secondary school context. Teachers conducted with pre and post-tests, and the responses show sessions were effective to practice of extensive reading with xreading.com. The pre/post-tests developed by MERA covered very general questions about extensive reading. While taking the pre-test in the beginning of the session, trainees were not expected to know the answers to all of the questions. When taking the same test as a post-test at the end of the same session, the trainees were expected to answer more questions correctly based on their received training with practices and activities. The open online module training met the expectations. For example, the 1st question asked 1821 participants about “In Extensive Reading approach, can the reader continue reading when he/she comes across few new words?” In the pre -test 50% of responses show the reader may stop reading to use dictionary. But in the post-test conducted with 1436 participants of the same session, 80,7% say the reader may continue the reading because of extensive reading resources. In short, extensive reading module trainings effectively promoted Mongolian secondary English education through online teacher development online held over 24 hours and containing two different modules with ER practices. The awareness raised among the foreign language methodologists, specialists, and study managers showed improved resource provision at educational online platform.