Background: Sleep is vital, but issues are mounting. Sleep deprivation is dangerous for hospital nurses. This reduces nurse productivity and increases patient-harming medical mistakes. Shift work affects sleep and circadian rhythms; therefore, night shift female nurses' sleep is important. Nurses and patients lose sleep amid disturbances. Objectives: The study examined night-shift female nurses' sleep quality. Methods: A cross-sectional study was conducted in Dhaka Medical College's Physiology Department from January to December 2019 among 160 female nurses aged 24-50 who work night shifts from 8 p.m. to 8 a.m. in In-patient department of Medicine, Surgery, Obstetrics, and Gynecology. Pittsburg Sleep Quality Index and nurse demographics were obtained. After informed consent was signed, the individual was thoroughly questioned and recorded in the predesigned data form. Statistics were done with Excel and SPSS-26. Results: Mean BMI was 23.91 ± 1.64 kg/m², and systolic and diastolic blood pressures were 105.63 ± 11.10 and 69.94 ± 6.68 mmHg, respectively, without statistical significance (p > 0.05). The Pittsburgh Sleep Quality Index (PSQI) components showed significant results (p < 0.001), with mean scores for subjective sleep quality (1.09 ± 0.35), latency (1.95 ± 0.84), duration (1.77 ± 0.72), and additional parameters resulting in a mean global PSQI score of 7.94 ± 1.76. Highest number of respondents were belonging to age group 31–40 and 68.75% were married and in medical wards (42.50%). The lowest sleep quality was seen in Obstetrics & Gynecological wards, with 54 nurses scoring over 5 on the global PSQI (p < 0.001). About 69% of nurses had a PSQI score > 5, suggesting poor sleep quality, associated with age, marital status, and ward type (p < 0.001). Conclusion: Female nurses need sleep hygiene instruction, shift schedule adjustments, and stress management to sleep better. These obstacles affect nurses' well-being and care quality.