Background Emergency care clinicians are expected to use the latest research evidence in practice. However, emergency nurses do not always consistently implement evidence‐based practice (EBP). An educational intervention on EBP was implemented to promote emergency nurses’ use of EBP, and the effectiveness of it was evaluated. Aims This study aimed to evaluate the effectiveness of an EBP educational intervention on emergency nurses’ EBP attitudes, knowledge, self‐efficacy, skills, and behavior. The study also examined learners’ satisfaction with the EBP educational intervention. Methods A randomized controlled trial with parallel groups with evaluations before the education, immediately after it, and 6 and 12 months after the education was conducted at four emergency departments in two university hospitals. The experimental group (N = 40) received EBP education while the control group (N = 40) completed self‐directed EBP education. The primary outcomes were emergency nurses’ EBP attitudes, knowledge, self‐efficacy, skills, and behavior, while the secondary outcome was satisfaction with the EBP education. Results Thirty‐five participants of an experimental and 29 participants of a control group completed the study. There were no statistically significant (p < .05) improvements and differences between groups in EBP attitude, self‐efficacy, or behavior immediately after the EBP education. At the 6‐month measurement point, the experimental group showed significantly better EBP attitudes, behavior, knowledge, and self‐efficacy than the control group. At the 12‐month measurement point, the improvements began to decrease. The groups also differed significantly in terms of participant satisfaction with how the teacher encouraged learners to ask clinical questions. Linking Evidence to Action The EBP educational intervention implemented in this study had a positive effect on emergency nurses’ EBP attitudes, knowledge, self‐efficacy, skills, and behavior. The effects of the education appeared the best 6 months after the education. After this point, the results began to decrease and approached baseline levels. EBP educational interventions designed for emergency nurses should apply various teaching strategies to improve their EBP attitude, knowledge, self‐efficacy, skills, behavior, and satisfaction with the education.