Introduction: Provision of palliative care to patients with advanced chronic diseases or old populations is suboptimal, which results in unnecessary suffering of and burden to patients, caregivers, and society. Low self-efficacy in palliative care among nurses is a factor affecting suboptimal utilization of palliative care. Poor knowledge is a factor affecting low self-efficacy in nurses. Attitudes may contribute to the relationship between knowledge and self-efficacy, but these relationships have been rarely examined in nurses. Hypothesis: Attitudes moderate the relationship between knowledge and self-efficacy in palliative care among nurses, controlling for covariates. Methods: Data were collected from 282 nurses (Median age: 29 years) regarding self-efficacy, knowledge, attitudes, and covariates (i.e., age, marital status, work experience, experience of advance directive [AD] education, experience of AD with relatives, experience of AD education for patients, and experience of AD counseling). Process v4.1 for SPSS was used to test the hypothesis. Results: The levels of self-efficacy (5.9 out of 10), knowledge (14.6 out of 21), and attitudes (48.0 out of 64) among nurses were moderate. Higher levels of knowledge (p = .026) and attitudes (p < .001), the interaction term of knowledge and attitudes (p = .041), and experience of AD counseling (p = .008) were significantly associated with higher levels of self-efficacy in palliative care (F = 5.643, p < .001, R 2 = .172), indicating the moderating effect of attitudes. The relationships between higher levels of knowledge and higher levels of self-efficacy were significant only in nurses with highly (p = .005) and moderately positive attitudes (p = .026), but not in nurses with lack of positive attitudes (Figure 1). Conclusions: The findings of this study supported the hypothesis. To improve self-efficacy in palliative care among nurses, improvement in knowledge and facilitation of positive attitudes are needed.