Cancer is the first cause of death by disease in childhood globally. The most frequent types of cancers in children and adolescents are leukemias, followed by brain and central nervous system tumors and lymphomas. The recovery rate of cancer in children is around 80% in developed countries and up to 30% in developing countries. Some of the main causes of complications in children and adolescents with cancer are respiratory viral infections, mainly in bone marrow-transplanted patients. Respiratory viruses have been detected in the bronchoalveolar lavage or nasal wash specimens from cancer patients with or without respiratory illness symptoms. Human metapneumovirus (HMPV) is within the ten most common viruses that are encountered in samples from pediatric patients with underlying oncology conditions. In most of cases, HMPV is found as the only viral agent, but co-infection with other viruses or with bacterial agents has also been reported. The discrepancies between the most prevalent viral agents may be due to the different populations studied or the range of viral agents tested. Some of the cases of infection with HMPV in cancer patients have been fatal, especially in those who have received a hematopoietic stem cell transplant. This review seeks to show a general view of the participation of HMPV in respiratory illness as a complication of cancer in childhood and adolescence.