<![CDATA[This study aims to (1) determine the differences in students' written mathematical communication skills based on their level of self-efficacy, (2) determine the differences in students' written mathematical communication skills based on gender differences, (3) determine the interaction between the level of self-efficacy and gender differences on written mathematical communication skills. This study is a survey research using a descriptive comparative research method. The population in this study consists of all 330 ninth-grade students at SMP Negeri 4 Samarinda. The sampling technique used in this study is nonprobability sampling. The sample for this study consisted of 178 students. Data analysis was conducted using descriptive statistics and inferential statistics employing a two-way ANOVA transformed using the Aligned Rank Transform (ART) method, as the data did not meet the assumption of normality. The results of the descriptive statistical analysis showed that the average score for mathematical communication ability among students with high self-efficacy was 17.79; moderate self-efficacy was 14.71; and low self-efficacy was 12.87. Based on gender, female students had an average score of 18.47, while male students had an average score of 11.28. The results of the inferential statistical analysis showed (1) there was a difference in students' mathematical communication skills based on levels of self-efficacy with a p-value of 0.040 (2) there was a difference in students' mathematical communication skills based on gender differences with a p-value of 0.000 (3) there is no interaction between self-efficacy levels and gender differences on mathematical communication skills with a p-value of 0.364.]]>
