In this study, the effects of the 11th Grade Sequences unit on Realistic Mathematics Education (RME) activities and the students' RME approach were investigated. It is envisaged that the study will reveal positive or negative student views about RME and increase student achievement in Sequences that is one of the most difficult subjects for students to understand. The study was carried out with 50 students in the 11th grade of a high school in Yeşilyurt, in Malatya in 2015-2016 academic year. In the experimental group (n = 25), the teaching was supported by Realistic Mathematics Education and in the control group (n = 25) the current teaching was applied. . Data were collected by using the equalization test, the pre-post achievement test, the pre-post attitude scale and the thought survey. In the analysis of the distribution normality of the data with SPSS package program, it was seen that the data were not distributed normally. So, the nonparametric test, Mann Whitney U and Wilcoxon Signed Rank Test, were used for the analysis of achievement test and equalization test. Thought survey results were interpreted by giving frequency-percentage distributions. As a result of the findings, it was determined that there was a significant difference between the experimental group students who studying with realistic mathematics education and the control group students who continued their current education in favor of the experimental group. According to the results of the thought questionnaire taken from the RME approach to the experimental group students, it was observed that the opinions of the students were positive.