It is crucial for students to develop their 21st-century skills such as technological literacy and critical thinking skills with various curricula to be updated in accordance with technology integration in education. Therefore, a critical thinking curriculum was designed, implemented and evaluated by using Web 2.0 tools for secondary school students. The research, adopting embedded mixed design [qual+Quan(qual)+qual] research model, was carried out with 21 secondary school students studying at 5th and 6th grades. Before the 8-week implementation process, a needs analysis was carried out, student journals during the implementation were analyzed with content analysis. A significant difference was found, in favor of the post-test, between the pre-tests/post-tests of "Critical Thinking Skills Test" and "Critical Thinking Disposition Instrument" as a result of Wilcoxon Signed Ranked Test analysis while there was no significant difference between the post-tests based on variables of grade and gender in the Mann Whitney-U analysis. In the content analysis of the student interviews carried out after the implementation, it is seen that students found the curriculum entertaining and gained awareness in utilizing critical thinking skills. In addition, students suggested activities embodying more verbal expressions and extracurricular assignments to be more active.Individuals who have critical thinking skills (CTS) are open to change, think alternatively, are curious, make realistic decisions by establishing a cause-effect relationship based on evidence, and have the self-confidence to discuss the reasons for their decisions (Facione, 1990;Yılmaz, 2019). It is a necessity to enrich the curricula with up-to-date knowledge, skills, and technologies so that individuals in the developmental age can acquire CTS (Larson & Miller, 2011;Voogt & Roblin, 2010). Accordingly, teaching/learning methods and materials along with the subject content need to be updated with the innovations in accordance with the age of technology (Dede, 2010). By developing curricula, so that new knowledge and skills are acquired in the social structure through the technological literacy skills that emerged with the rapid progress in the information technologies in the 21 st -century and