Despite the buzz around the flipped or inverted classroom as a new trend in educational practice and research, there is a limited number of studies on its effectiveness in English as a Second Language (ESL) teaching. This paper aims at contributing to the field of flipped classroom research by briefly examining and analyzing the outcomes of the experiment conducted at the Tomsk Polytechnic University within the course of English for Engineering. Outlining several challenges, the authors conclude on the significant benefits of the flipped classroom in ESL teaching including an increase in students’ overall performance on the course, enhancement of students’ motivation and improvement of their autonomous learning skills.