Thinking is the process of deciding what to believe or what to do by making sense of the current situation as an action that keeps the brain functioning continuously (Cüceloğlu, 1999). Thinking, which is a mental product, realizes thanks to the interactions between elements that exist in the mind, and if adaptation, reasoning or judgment is to be made, it reaches the result by activating affective inputs in mental processes (Jones, 2019). Environmental factors, education level and social environment are important factors in the development of an individual's thinking skills (Özdemir, 2005). It is divided into many different types in terms of thinking, purpose and skills. For example; creative thinking, critical thinking, analytical thinking, metacognitive thinking, divergent thinking, convergent thinking, lateral thinking, algorithmic thinking and critical thinking (Çiftçi, 2017). According to NACE (2017), employers rated the need for critical thinking/problem solving as the most needed competency for career readiness. During the last two decades students at higher education are being more exposed to the concept of critical thinking as a way to improve not only their professional skills, but their personal competencies as members of a global community (Altuve, 2010; Crenshaw, Hale, & Harper, 2011; Facione, 2013; Moore, 2013; Villarini, 2003). Halpern (2014) warns that in our era, in which a myriad of knowledge can be easily accessed at one click, it is important to teach students to be critical and effective thinkers. Critical thinking is usually related to other skills that are considered key in the 21st century in students’ learning process, with stakeholders, and in everyone’s family life: metacognition, motivation, and creativity (Moeti, Mgawi, & Mealosi, 2017). Critical thinking is a competence student need in their personal and professional lives. Therefore, universities should do their best to include this in their teaching programs and classroom practice. Since there is no clear definition of critical thinking competence and many new methodologies need to be developed to develop this skill, it seems to be an issue that educators should focus on for many years (Bezanilla, et al., 2019). This study was conducted on the classroom teacher candidates' levels of using critical thinking skills through advertisements. This work was carried out with 14 teacher candidates in 3rd grade, the classroom education department of a university in South Anatolia region in Turkey. Before the data were collected, a questionnaire study was carried out on how to reflect their critical thinking skills to prospective teachers in the most comfortable way. This survey included topics such as social problems, covid-19 process, cultural values, our education life, personal development, individual needs, global problems, communication problems and advertisements. Since it was concluded that more than half of the students participating in the study chose the subject of advertising, this study was conducted on advertisements. The opinions and critical approaches of the advertisements given to the pre-service teachers to watch and interpret were analyzed. When the results were examined, it was concluded that the advertisements of the teacher candidates were generally gathered in the themes such as violation of ethical values, products that do not reflect the truth, subliminal messages, gender inequality, and women's body preemptive of products. In general, it can be said that pre-service teachers can look at advertisements critically, but some of them have very superficial implications. The reason for the pre-service teachers' such shallow answers may be that they have not received any thinking training throughout their education. For this, at least after high school education, it can be suggested that the courses with the content of thinking education should be included in the curriculum.