Most newly diagnosed cancers occur in older adults, and it is important to understand a patient's underlying health status when making treatment decisions. Therefore, clinicians need enhanced competencies and skills to effectively care for this population. However, most clinicians receive minimal to no training in geriatrics. This study aims to evaluate the education and training levels in geriatric oncology among Turkish physicians and to understand the factors influencing oncologists' treatment decisions for geriatric cancer patients. A 24-question survey was prepared to obtain the participating physicians' demographic information, as well as to inquire whether they had received training during their medical education and residency on how to approach geriatric patients, in what process(es) they had received the training, whether they were currently treating geriatric patients, what they focused on when evaluating geriatric patients, and what they thought about their training and preparedness for approaching geriatric patients. The questionnaire was sent online to radiation and medical oncologists, and the link was published on the Turkish Society of Radiation Oncology and the Turkish Society of Medical Oncology websites. Two hundred and three physicians participated in the survey, 131 of whom were women. The median age was 41.66 years (24-69 years). One hundred and fifty-six physicians (76.1%) received specialty education at the university hospital. One hundred and three of them were radiation oncologists, and 80 were medical oncologists. Of the physicians, 19.7% received education in geriatrics before they specialized in oncology, and 6.9% said they were educated after specialization. When determining suitability for radiotherapy, 10.7% of radiation oncologists said that they use geriatric assessment tools. Similarly, 13.8% of medical oncologists claimed that they used geriatric assessment tools in determining suitability for chemotherapy. Of the physicians, 177 (86.3%) thought that geriatric evaluation could independently increase patient survival rate. Furthermore, patient cognitive status, functional status, physiological age, polypharmacy, geriatric specialist recommendations, inpatient services, patient relatives, and similar factors were found to be useful in treatment decisions. Finally, 92.7% of the participants believed that receiving education would have changed their perspectives on treating geriatric patients. Our results provide perspectives on developing knowledge on and skills in geriatric training among oncologists. Learning new approaches is necessary for oncologists who more frequently confront geriatric patients with cancer.