Background: Chemotherapy is commonly used in combination with other treatments for breast cancer. However, low adherence to chemotherapy is a growing concern, particularly among breast cancer patients. Side effects such as nausea and vomiting, fatigue, and arthralgia can contribute to reduced adherence. Other factors such as provider communication and limited insurance coverage can affect adherence. Studies have shown that as much as 28% of patients with breast cancer did not continue with their prescribed dose of chemotherapy. Research suggests that chemotherapy education materials can be critical to addressing problems with non-adherence, and may include written materials, verbal instruction, and multimedia programs. Despite this wide variety, the effectiveness and benefit of chemotherapy education hinges on the patients' health literacy. Breast cancer patients with low health literacy may be unclear about chemotherapy or face difficulty adhering to treatment if they do not understand the information provided to them. Thus, this scoping review summarizes the existing research on how health literacy principles are incorporated into breast cancer chemotherapy education materials. Methods: Using a combination of keywords (e.g. chemotherapy, education) and Medical subject headings (MeSH) terms (e.g., drug therapy, antineoplastic agents), we searched five databases : CINAHL, PubMed, PsycINFO, Cochrane Library, and Web of Science. Results: Eight of 4,624 articles met the inclusion criteria. Five articles incorporated health literacy principles (e.g., plain language, maintaining an active voice, using white space) into the development of written materials. Few articles used a theoretical framework to guide education material development (n = 3). Of the three articles that described pilot-testing of educational materials, two used post-tests only and one used a pre/post-test design. Conclusions: Findings indicated that limited research exists regarding the use of health literacy principles in chemotherapy education materials. Much of the development of chemotherapy education is not grounded in theory and the application of health literacy principles is limited. Implementing health literacy principles may improve overall comprehension of education thereby increasing adherence.