Objective: This study aimed to understand the experiences of oncology patients and their perceptions about the relationship between their mental health and the current state of their cancer, and the impact the COVID-19 pandemic has had on their mental health, disease state, and overall well-being. Method: A qualitative study utilizing a basic interpretive approach was conducted, which included individual semi-structured interviews with seven participants that were undergoing treatments and diagnosed with cancer of any type and at any stage prior to the start of the COVID-19 pandemic. Interviews were conducted using a semi-structured interview guide to capture the participants’ experiences with their mental health and quality of life in relation to their cancer diagnosis. Results: Six major themes emerged from the interviews and included: emotional overwhelm, fear of the unknown, learning to adapt to a new normal, maintaining a positive outlook, the impact of the COVID-19 pandemic, and mental health not being addressed as part of the standard of care in oncology. The findings suggest that a significant proportion of oncology patients experience mental illnesses present at all stages of their cancer journey and increase during periods of longer and more intense treatment cycles. Conclusions: The results of this study highlight the need for comprehensive mental health care that is integrated into cancer care. They also demonstrate the importance of addressing the mental health needs of cancer patients throughout the entire cancer journey to improve the quality of life for cancer patients and their overall well-being.