This study aims to describe the influence of contextual learning model and critical thinking ability toward argumentative writing skill on university students. The population of the research was 147 university students, and 52 university students were used as sample with multi stage sampling. The results of the research indicate that; group of contextual learning model has more significant influence than group of non-contextual learning model, there is an interaction between learning model and critical thinking ability, there is a significant difference of argumentative writing skill between group of contextual learning and non-contextual learning for the group with high critical thinking ability, and there is also significantly different argumentative writing skill between contextual learning and noncontextual for the group of low critical thinking ability. Based on this finding, the researcher concludes that critical thinking ability and contextual learning model have significant influence toward argumentative writing skill.