Inquiry-based learning in Slovak schools is still considered to be an innovative approach to teaching based on the active exploration of new knowledge by pupils themselves. It allows deeper involvement of pupils in the learning process, encourages motivation and differentiation with respect to individual learning preferences, creates space for pupils to develop cooperation and communication skills. Inquiry is a natural cognitive process for pupils, but its wider application is mostly in biology, chemistry or physics classrooms, while computer science in Slovak schools is still dominated by instructive teaching strategies. In the frame of the National project IT Academy we have focused on different fields of the computer science curriculum and we have implemented the 5E instructional model as an inquiry-based learning approach in 40 primary school lessons and 40 secondary school lessons. We provide teachers with complete lesson plans, including worksheets, supplementary work files and materials, or reference materials. These educational materials are being tested by teachers in Slovak schools. For both primary and secondary school teachers, we organize also professional development courses on innovative teaching strategies in the computer science classroom to make it easier for them to implement these new classroom learning practices. This paper presents the results of a survey on teachers’ perception, attitudes, experiences, misconceptions and barriers to inquiry-based teaching strategies in computer science classrooms as the classroom teacher plays a key role in the successful implementation of these new learning strategies. Our research investigates how different factors affect teachers when considering the inquiry-based learning and its successful implementation in computer science classrooms highlights two major underlying factors, the teacher’s personal contribution factor and a factor representing a collection of the teacher’s readiness and teaching skills, which are further discussed.