Language plays an important role in understanding word problems in mathematics. Familiarity or lack of it may determine the success or failure in understanding and working out word problems. This study was conducted to know the difference in the performance of 4th Grade pupils when word problems in mathematics are expressed in English language and Mother Tongue-Based language (Hiligaynon). Descriptive-comparative statistics was used in the study. Qualitative design was also used. The participants were divided into two groups; one group took the test expressed in English language and the other group took the test expressed in Mother Tongue-Based language. Result showed that there is no significant difference when word problems are expressed in English language and Mother Tongue-Based language. However, the registered mean for the two groups were below proficiency level which may imply that both groups had experienced difficulty in solving word problems regardless whether the itemsare expressed in English language or in Mother Tongue-Based language. Findings further showed that students from the two groups were able to answer easier items and both groups found