Hallucinations require comprehensive nursing interventions to support symptom management and promote patient functioning. Generalist Hallucination Therapy is a structured nursing approach, however, its implementation may vary across clinical settings. This study aimed to examine factors associated with nurses' implementation of Generalist Hallucination Therapy at Radjiman Wediodiningrat Hospital, Indonesia. A quantitative cross-sectional study was conducted among 61 psychiatric inpatient nurses selected through proportionate random sampling. Data were collected using questionnaires assessing demographic characteristics, knowledge, and attitudes, and an observational instrument evaluating therapy implementation. Bivariate associations were analyzed using Fisher's exact test, while multivariable analysis employed Firth penalized logistic regression to address sparse data and complete separation. The results showed that 57.4% of nurses demonstrated good therapy implementation. In the bivariate analysis, length of service was significantly associated with implementation (p = 0.030), whereas education, knowledge, and attitudes were not significantly associated. However, in the multivariable model, length of service (adjusted OR = 3.328; 95% CI: 0.665–20.728; p = 0.143), knowledge (adjusted OR = 2.951; 95% CI: 0.379–32.778; p = 0.293), and attitudes (adjusted OR = 2.025; 95% CI: 0.089–329.474; p = 0.677) were not statistically significant. The wide confidence intervals indicated substantial uncertainty in the estimated associations. Although length of service was associated with therapy implementation in the bivariate analysis, no independent associations were statistically significant in the full multivariable model. Further studies with larger samples are needed to clarify the factors associated with the implementation of Generalist Hallucination Therapy.