Background: Breakthrough cancer pain (BTCP) is a transient, severe pain episode that occurs above the baseline pain managed by ongoing analgesics. This study was conducted to learn the clinical practices of oncology nurses regarding the recognition, evaluation, and management of BTCP and to determine the factors affecting their pain self-management. Design: A descriptive and correlational cross-sectional study. Methods: The study was carried out between March and October 2024 with a sample of 148 nurses providing care to cancer patients. Data were gathered through three instruments the BTCP Identification Form, the Opioid Drug Applications Perception Scale, and the Pain Self-Management Scale. Results: A total of 58.2% of the participants reported that they had never heard the term BTCP, while 37.2% identified it as a sudden, severe, and transient exacerbation of pain occurring despite controlled baseline pain. The mean score on the Pain Self-Management Scale was 85.67 ± 13.66. Statistical analysis revealed that nurses’ educational level and prior training in pain management were significantly associated with higher pain self-management scores (p < 0.05). However, age showed a slight but statistically significant positive correlation with pain self-management scores (p < 0.05). Conclusion: The findings indicate a limited awareness and understanding of BTCP among nurses, particularly in differentiating BTCP from baseline pain. This knowledge gap may undermine effective pain assessment and management in clinical practice. Tailored educational interventions focusing on the recognition and management of BTCP are recommended to enhance nurses’ competencies in cancer pain care.