Mathematics anxiety is an affective condition that may be associated with students’ academic performance in mathematics. This study aimed to examine the relationship between mathematics anxiety and mathematics learning outcomes among upper-grade elementary school students. A quantitative research method with a correlational approach was employed. The participants were 23 fifth-grade students selected from four elementary schools using purposive sampling. Mathematics anxiety data were collected using a questionnaire covering cognitive, somatic, and attitudinal dimensions, while mathematics learning outcomes were obtained from students’ mathematics final examination scores. Descriptive and inferential analyses were conducted using IBM SPSS Statistics. The Shapiro–Wilk normality test indicated that the data were not normally distributed. Therefore, Spearman’s rank correlation was used as the primary hypothesis-testing procedure. The analysis produced a significant negative correlation between mathematics anxiety and mathematics learning outcomes (? = ?0.625, p = 0.001, two-tailed). The findings indicate that students with higher levels of mathematics anxiety tend to obtain lower mathematics learning outcomes. However, the interpretation of the findings should be made cautiously due to the small sample size, non-normal data distribution, and limitations in the reported reliability of the measurement instrument. The findings highlight the importance of supportive and student-centered mathematics learning environments that may help reduce students’ anxiety and facilitate their engagement in mathematics learning.