This study aimed to investigate differences in the mathematical problem-solving and metacognitive skills of the fifth-grade students in Oman as a function of gender and level of academic achievement. The participants were 90 grade five students randomly selected from one educational governorate in the Sultanate of Oman. They were evenly divided into three groups based on gender and levels of academic achievement. Four instruments were used in the study: a mathematical problem-solving test, a non-verbal metacognitive scale, Raven Coloured Progressive Matrices and a long-term memory test. The results for metacognitive and mathematical problem-solving skills indicate that students with a high level of academic achievement obtained the highest score while students enrolled in a learning disability program obtained the lowest score. In addition, possible interventions were identified that may improve the metacognitive skills of students enrolled in the learning disability program, which could lead to improvement in their mathematical problem-solving skills.