Mobile technology opens a new avenue for teaching and learning mathematics in schools in the 21st century. This study determined the effects of using a mobile application in teaching mathematics among Grade 8 students of a public national high school, Cebu City, Philippines. The researchers used the quasi-experimental method of research using the pretest-posttest design. It used two groups of subjects with 40 students per group. The students were enrolled in Grade 8 mathematics. Frequencies, simple percentage, mean, standard deviation, rank, and t-test were used to treat the gathered data. The study revealed that there is an increase in the posttest scores of the control and experimental groups. It was concluded that the use of the mobile application in teaching mathematics to Grade 8 students had helped enhance students' achievement and learning. The researchers recommend that the proposed action plan be used and monitored to help students in mathematics.