There is little knowledge about breast cancer patients' information-seeking behaviors, needs, and perceptions of breast radiation therapy (BRT) prior to radiation oncology consultation. This study assessed these parameters to evaluate potential gaps and overlaps in the BRT educational process. Breast cancer patients > 18 years referred for adjuvant BRT at a tertiary cancer center completed an anonymous survey prior to their consultation. Response rate was 86% (118/137). The most commonly reported sources of information about BRT were healthcare providers (55%), family or friends treated with BRT (53%), and the Internet (45%). Most (79%) had little or no knowledge about BRT. Sixty-seven percent were a little or moderately concerned about BRT, while 29% were very concerned. Half were unsure about the benefit of BRT and 46% thought it would provide a moderate to significant benefit. While seeking information about BRT, a wide range of topics were encountered. The most common ones were fatigue (68%), skin care (57%), skin problems (54%), effects on healthy body tissues (43%), the immune system (37%), and pain (34%). Topics considered most important for the radiation oncologist to address were BRT effects on the heart (74%), second cancers (74%), immune system (66%), pain (64%), and lungs (62%). Although commonly encountered, fatigue (56%) and skin care (49%) were of lesser importance. In conclusion, breast cancer patients encounter a broad range of information about BRT prior to their radiation oncology consultation, which may contribute to worry and misconceptions. Potentially rare and serious side effects were considered important to address.