Language plays an important role in the development of mathematics. Previous research has shown that both basic and advanced linguistic skills relate to fifth-grade advanced mathematics (i.e., geometry and fractions), but these effects have not yet been investigated longitudinally or in a linguistically diverse population. The present study first examined the differences between first-language and second-language learners in advanced mathematics. Second, we investigated the extent to which the basic and advanced linguistic skills of first-language and second-language learners directly and indirectly (through arithmetic) predict their growth in advanced mathematics from fifth to sixth grade. Participants were 153 first-language and 80 second-language learners from 10 to 12 years of age. Classroom as well as individual measures were administered. First, the results showed lower scores for second-language learners on advanced mathematics. Second, for both groups of language learners, basic linguistic skills were found to indirectly predict the growth in advanced mathematics via arithmetic skills, whereas advanced linguistic skills directly predicted the growth in geometry and fractions. These results highlight the general need for opportunities to learn the basic and advanced linguistic skills associated with mathematics over individual native language background. Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.