Critical thinking is a higher order cognitive skill which helps in processing the information. The focus of the study is to examine the relationship between critical thinking skills and achievement in the physics of the higher secondary students in which the sample consisted of 300 higher secondary students from Villupuram District of Tamil Nadu by using the stratified sample technique. Murthy critical thinking scale (2015) was used to collect the data. The descriptive research method was used and the data were analyzed by ‘t’ test, ANOVA and Pearson’s product moment co-efficient correlation test. The result showed that there was a significant positive relationship observed between critical thinking and achievement in physics, which confirms that critical thinking skills would help in learning physics. Analysis based on gender and types of school showed that there is no significant difference among higher secondary students in their critical thinking skills. In achievement in physics, there was no significant difference with respect to gender, but there existed 1% significant difference between higher secondary students with respect to school types which reveals that schools play an important role in increasing achievement among students. Study divulged that teachers must be mastered over the critical thinking skills to inculcate these skills among students to increase their achievement in physics.