Patients undergoing chemotherapy are at risk for malnutrition and a high symptom burden, and nutritional interventions can address clinical and supportive care outcomes. Herein, we identified barriers and facilitators to adhering to a Mediterranean Diet (MedDiet) intervention during chemotherapy. Patients with cancer (any type) who were undergoing chemotherapy were enrolled into a clinical trial testing the effects of an 8-week MedDiet intervention on cancer-related fatigue. Participants were randomized 2:1, MedDiet:control. The intervention entailed food provision, education, a cookbook, a session with a nutritionist, and weekly check-ins. Post-intervention, all participants completed semi-structured exit interviews. The interviews were transcribed and open coding was conducted to describe the facilitators and barriers to MedDiet adherence. Participants (n = 29, n = 21 in the intervention group) were 51.0 ± 15.1 years old and 93.1% had breast cancer. Educational materials and convenient food delivery were the highest reported facilitators. Many patients offered that changing their diet gave a sense of control and empowerment. Barriers to adherence were that the frozen food was unappetizing, participants' (or their spouse/children's) food preferences did not align with the MedDiet, and chemotherapy-induced side effects that prevented food consumption (eg, mouth sores, lack of appetite). This project helps understand the patient experience within nutritional interventions to optimize dietary programs during chemotherapy treatment.