As critical thinking becomes a crucial element in determining the success or failure of any educational system, investigating its status and level of integration in the teaching and learning process becomes, in tandem, urgent. Thus, this study investigated the extent to which critical thinking skills are integrated into English language education in cycle one of the basic education system in Oman. The analysis targeted the case of Grade 4, second semester textbooks. The study also examined the level of cycle one EFL teachers' knowledge about critical thinking and their perceptions about the level of their incorporation of critical thinking skills into their practices. Two instruments were implemented for this study: (1) a content analysis checklist that adopted Facione's (1990) model of critical thinking skills to answer the first research question, and (2) a questionnaire that collected data to address the second, third, fourth, fifth, and sixth research questions. An electronic version of the questionnaire was developed and distributed to cycle one EFL teachers in Addakhiliya Governorate in the 2020/2021 academic year. Because only female teachers teach cycle one, the sample of the study consisted of 203 EFL female teachers. The results indicated that the level of critical thinking skills integration in Grade 4B textbooks is 35.55 %. Similarly, the study revealed that cycle one EFL teachers have an average knowledge level about critical thinking. In terms of teachers' practices from their point of views, the findings revealed that the questions and activities that teachers present to their students integrate critical thinking at an average level; however, the teachers demonstrate a high level of behaviors and responses that incorporate critical thinking. The results also showed that teachers considered class size, workload, textbook tasks, and training and professional development challenges to critical thinking implementation. Based on these findings, the researcher outlined several recommendations and suggestions for further research.