Often, cancer patients do not receive education about the negative consequences of smoking on the treatment outcome. To support cancer patients in the process of smoking cessation, it is essential to involve oncology staff. This study aims to learn about the experiences and attitudes from the point of view of oncology staff and, thus, how a smoking intervention should be designed. The study aims to engage all oncology staff due to the unclear responsibility for providing smoking cessation education, support, and motivating cancer patients to quit smoking. N = 354 German oncology staff (oncologists, nurses, psycho-oncologists, others) filled out a 5-point Likert scale-based questionnaire regarding practices, potential barriers, and attitudes towards smoking cessation between October 2021 and June 2022. The questionnaire was developed by Derksenet al. (2020), translated and slightly modified for the use of this study. It was distributed to all leading oncology staff in our Cancer Center Network with a request to share with alloncology staff. Flyers were also handed out in all oncology wards and outpatient clinics in the same Cancer Center Network. Most oncology staff ask cancer patients about their current smoking status (curative, M = 2.27; SD = 1.59; palliative, M = 2.90; SD = 1.83), but they rarely treat or refer patients for a smoking cessation intervention (curative, M = 4.78; SD = 1.20; palliative, M = 4.99; SD = 1.06). Smoking behavior of curative cancer patients is addressed more than that of palliative cancer patients (d = - 37). Regression analyses of key dependent variables showed that profession, setting, and the belief that continued smoking affects treatment outcome explained the variance of asking patients if they smoke, advising to stop smoking and lack of time (without profession). Involving oncology staff in motivating cancer patients who smoke to quit and referring them to smoking cessation services should take the different attitudes and knowledgeof the staff into account to improve treatment that supports tobacco cessation. Cancer patients have special needs when it comes to a cessation program. In the long term, survivors will benefit from tailored smoking cessation education and services provided by oncology staff to help them quit smoking after a cancer diagnosis.