This study aims to know the correlation between: (1) students’ anxiety and writing skill, (2) grammar mastery and writing skill, and (3) students’ anxiety, grammar mastery simultaneously, and writing skill of the seventh grade students of  MTs Negeri 2 Surakarta. This study involved 30 students that were selected by using cluster random sampling. In collecting the data, the researcher used questionnaire and test. Single Correlation and Multiple Linear Regressions were used for analyzing the data. The result of the research demonstrates that: (1) students’ anxiety contributes 12.80% to writing skill; (2) grammar mastery contributes 14.91% to writing skill; and (3) students’ anxiety and grammar mastery simultaneously contributes 33.81% to writing skill. Based on the study, it can be assumed that students’ anxiety and grammar mastery are important elements that give contribution to writing skill.