The idea is growing among educators that thinking skill needs to be given a direct attention. On one hand, critical thinking is supposed to broaden students’ thinking in all regards (Schafersman, 1991); and on the other hand learners’ attitudes towards the second language can affect both their performance in the class and their final accomplishment. To this end, the present study started with the question of whether the application of critical thinking ability to English classes could affect learners’ second language attitudes. The study was designed and conducted at an English language Institute. 4 classes were selected randomly (2 female and 2 male classes). They were divided into two experimental and control groups. In experimental classes learners practiced critical thinking skills, which was absent in the control group. Critical thinking principles were applied through 21 strategies developed by Ennis (2011). FLAGS (Foreign Language Attitudes and Goals Survey) questionnaire (Eva Cid, Gisela Gran˜ena, Elsa Tragant, 2009) was given to students, both at the beginning and at the end of the semester, which were considered as the pre and post-tests for statistical computations. The results revealed a significantly higher second language attitude in participants who went through critical thinking instruction. In addition, applying critical thinking skills in the class affected students’ level of goal orientation in terms of learning a second language. The research encourages English language teachers to incorporate critical thinking skills into their instructions.