External beam radiotherapy (EBRT) commenced in West Africa with the provision of Cobalt-60 teletherapy (CO) treatment at Lagos University Teaching Hospital, Nigeria in 1973. No analysis of the trend in EBRT capacity specific to this region, including the installation of linear accelerators (LINACs), has been performed to date. The purpose of this study is to present the number of megavoltage units (MVUs) in West Africa from 1979 to 2019. West Africa was defined in accordance with the United Nations delineation and inclusive of Benin, Burkina Faso, Cabo Verde, Cote d’Ivoire, The Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, and Togo. A literature search for publications detailing the number of MVUs in West African radiotherapy centers was performed, and extracted MVU data were confirmed using the Directory of Radiotherapy Centers (DIRAC). Population data were obtained from the Word Bank Group and used to determine the number of MVUs per 100 million persons. Nine of 16 (56.3%) West African countries have no history of EBRT, and one country (Liberia) lost its treatment capacity. The number of operating MVUs in 1979, 1989, 1999, 2009, and 2019 were 1, 2, 5, 8, and 22, respectively. Five centers currently house 2 MVUs, including 2 centers which offer both CO and LINAC treatments. The largest absolute decrease EBRT capacity occurred from 2014 to 2017 during which 1 CO unit was decommissioned and 6 MVUs (1 CO unit and 5 LINACs) were deemed non-functional. The largest absolute increase in EBRT capacity occurred from 2017 to 2019. In this interval, LINACs were installed in Cote d’Ivoire (2), Ghana (2), Mauritania (1), and Senegal (3). In Nigeria, 2 CO units and 5 LINACs were either commissioned or rehabilitated. When MVUs known to be non-functional were excluded, the numbers of MVUs per 100 million persons were 1.3 in 1979, 1.1 in 1989, 2.2 in 1999, 2.7 in 2009, and 5.6 in 2019. West African nations have experienced an increase in the absolute number of MVUs installed in public and private centers in the last 40 years. However, the MVUs-to-persons ratio is still well below the ideal ratio of 1 MVU per 250,000 persons recommended by the International Atomic Energy Agency. As non-functional LINACs contributed to a marked decline in the EBRT infrastructure of the region from 2014 to 2017, a strategy of dual use of CO/LINAC technologies may act to ensure the availability EBRT treatment in centers with capacity for multiple MVUs.