Background Nurse-patient communication is one of the most important care relationships that affects the treatment process. The health action process approach (HAPA) has been used to explain a number of behaviors. However, this approach has not been used to explain nurse-patient communication. Therefore, this study was conducted to investigate effective nurse-patient communication using this approach. Materials and methods In this cross-sectional study, 300 nurses from public hospitals in the center of Iran were enrolled in the study. A researcher-developed questionnaire was used to measure the HAPA constructs. The data were analyzed using Pearson's correlation coefficient and one-way analysis of variance with least significant difference (LSD) post hoc tests in SPSS as well as structural equation modeling using AMOUS software. Results In the motivation phase, risk perception, outcome expectancies and task self-efficacy predicted 19% of variance in intention to communicate effectively. In the volitional phase, planning and action self-efficacy predicted 22% of variance in effective communication. The scores of HAPA constructs were different depending on the levels of effective communication. Conclusions The model can serve as a reference framework to promote effective nurse-patient communication.