The present study explored the impact of WebQuest-based classroom on EFL learners' critical thinking and academic writing skills by collecting and analysing the data through a sequential explanatory mixed-methods approach. Two intact classes, each with ten EFL learners, attending an IELTS course at a language institute in Sanandaj, Iran, took part in the study. California Critical Thinking Skills Test form B was used to assess the participants' critical thinking skills, IELTS academic writing task 1 and task 2 were used to assess their academic writing skills, a semi-structured interview was conducted to assess their perceptions towards the impact ofy the WebQuest-based classroom on critical thinking and academic writing skills, and the researcher/instructor journals were used to contribute to the qualitative findings. One-way MANOVA and one-way MANCOVA were used to analyse the quantitative data. The results revealed that both the WebQuest-based and the face-to-face classrooms developed the learners' critical thinking and academic writing skills, while the former outperformed the latter both in post- and delayed post-tests (i.e. short and long term effects) and took fewer sessions to cover the required materials. In addition, thematic analysis, used to analyse the qualitative data, uncovered a number of themes which addressed the learners' positive perceptions towards the impact of the WebQuest-based classroom.