Purpose This study aimed to develop and evaluate the effectiveness of a therapeutic communication program based on King’s goal attainment theory, specifically designed for nurses providing care to patients with hematological oncology in a tertiary hospital setting. Methods: A non-equivalent control group design was employed, involving 59 nurses (intervention group: 29, control group: 30) with experience in hematological cancer care. The therapeutic communication program, developed according to the theoretical constructs of King’s theory, consisted of eight weekly sessions. Outcome variables included problem-solving ability, communication self-efficacy, and interaction satisfaction. The effects of the intervention were analyzed using the independent- and paired-samples t-test as well as a Wilcoxon signed-rank test. Results: In between-group comparisons of pre–post changes, communication self-efficacy increased significantly more in the intervention group than in the control group (p=.027). However, no significant between-group differences were found for problem-solving ability or interaction satisfaction. These findings suggest that the program effectively enhances therapeutic communication competencies among nurses in hematological oncology wards. Conclusion: The therapeutic communication program significantly improved problem-solving ability, communication self-efficacy, and interaction satisfaction among nurses in the intervention group within the hematological oncology ward. This theory-based intervention provides an evidence-based framework for strengthening clinical nursing practice and education.