Although cancer management is becoming more structured with disease-specific guidelines and clinical pathways, many decisions remain complex. Contributing to this complexity is the need to make value tradeoffs between benefits and harms across cancer treatment and/or screening options. Since there is no "best" option for everyone, decisions are defined as being of higher quality when informed with the latest scientific evidence and based on patients' informed values associated with outcomes of options. However, clinicians are not good judges of patients' values, and patients often have inadequate knowledge, unrealistic expectations, and decisional conflict that interfere with their involvement in decision making. Effective approaches to support patient involvement into clinical decisions include clinicians trained in shared decision making, question prompt sheets, patient decision aids, and decision coaching by nurses and other allied health professionals. Based on systematic review of 23 randomized trials of cancer patient decision aids, patients exposed to decision aids are more likely to participate in decision making and achieve higher-quality decisions. This review highlights key historical changes leading to patient involvement in decision making, summarizes evidence on effective interventions to support shared decision making, explores strategies to implement these interventions in oncology practices, and identifies future directions.