Cancer is one of the major medical challenges, with an unacceptably high death toll worldwide. In Morocco, medicinal plants continue to play a pivotal therapeutic role despite the development of modern sanitation systems. In the current study, an ethnobotanical survey was carried out at the Moroccan national institute of oncology, Rabat, and we aimed at (1) establishing an exhaustive inventory of indigenous knowledge of Moroccan medicinal plants used to manage cancer and (2) confirming the reported ethnopharmacological uses through bibliometric review. An ethnobotanical survey was conducted with 291 cancer patients at the Moroccan National Institute of Oncology, Rabat, during a period of 4 months, from February to May 2019, through semistructured interviews. Ethnobotanical indices, including informant consensus factor (FIC), use report (UR), relative frequency citation (RFC), botanical family use value (FUV), fidelity level (FL), and index of agreement on remedies (IAR), were employed in data analyses. The survey revealed that 39 medicinal plants belonging to 27 botanical families and 38 genera were used to treat cancer. The most used ethnospecies were Aristolochia longa with the highest RFC value (0.096), followed by Nigella sativa, Ephedra alata, Euphorbia resinifera, and Lavandula dentata, éwith RFC values of 0.072, 0.054, 0.044, and 0.044, respectively. In regard to the plant families, Lamiaceae contributed the highest number of plants with five species (FUV = 0.034), followed by Asteraceae (4 species; FUV = 0.020), and Fabaceae (4 species; FUV = 0.020). The leaves are the most popular plant part used by the studied population against cancer; otherwise, decoction was the most commonly used method for remedy preparation and the highest FIC was noticed for uterine cancer treatment (0.86). Considering these findings, further investigations into the recorded plant species should be performed to assess phytochemical constituents and pharmaceutical benefits in order to identify their active compounds for any drug formulations.