A growing body of research suggests that children's understanding of mathematical language is critical for their mathematical abilities. Most of this work has been restricted to single language learners (i.e., SLLs), and used dual language learners (i.e., DLLs) as an exclusion criterion, raising questions about the generalizability of these findings to DLLs. This is particularly important given the observed differences in the association between general language and mathematics for DLLs as compared to SLLs. In our study, conducted in Belgium, we therefore investigated the associations between components of mathematical language and different mathematical abilities in 75 DLLs and compared them to 75 age- and sex-matched SLLs (M[subscript age] = 4 years 8 months; 33 females in each group). Unfortunately, the two groups could not be matched on socioeconomic status (i.e., SES), and SES-levels of the parents of DLLs were significantly lower than SES-levels of SLLs. We assessed children's quantitative and spatial language, their mathematical abilities (numerical competencies, geometry, and measurement), as well as their general vocabulary and spatial skills. All children, including DLLs, were only tested in the language of instruction (i.e., Dutch) in which DLLs exhibited varying levels of proficiency. Results revealed that DLLs obtained lower scores than SLLs in quantitative and spatial language, mathematical abilities, general vocabulary, but not in spatial skills. Associations between components of mathematical language and mathematical abilities were similar across DLLs and SLLs, except for the relation between spatial language and geometry, which was weaker in DLLs.