Background <p>Research on shared decision-making (SDM) mainly focuses on physicians and patients, with less study on advanced practice nurses (APNs), who have expertise and participate in decision-making. Understanding APNs’ SDM knowledge, attitudes, and behaviors could enhance patient outcomes, especially in Taiwan where patient involvement in medical decisions is limited. This study examined how SDM knowledge, attitudes, and behaviors influence SDM implementation among APNs in Taiwan.</p> Methods <p>This study aims to examine the factors influencing and the relationships among SDM knowledge, attitudes, and behaviors of Advanced Practice Nurses (APNs) in Taiwan. This study employed a cross-sectional design and surveyed 112 Advanced Practice Nurses (APNs) in Taiwan via an online survey. Data collected via a questionnaire on SDM knowledge, attitudes, and behaviors were analyzed for influencing factors. Descriptive statistics and univariate linear regression were used.</p> Results <p>Attitude was the primary predictor of SDM behavior, strongly linked to effort and the quality of implementation. Practical SDM experience also boosted APNs’ effort in carrying out the process. This study identified gaps in APNs’ risk communication knowledge, especially in understanding relative risk and natural frequency formats.</p> Conclusions <p>SDM training should incorporate risk communication strategies, reflective learning, simulations, practice, and structured feedback to enhance APNs’ understanding of SDM core concepts and promote consistent clinical application.</p> Clinical trial number <p>Not applicable.</p> Trial registration <p>Not applicable. This study did not involve any health care intervention on human participants.</p>