There is variable and suboptimal use of fascia iliaca compartment nerve blocks (FICBs) in hip fracture care. Our objective was to use an evidence-based and theory-informed implementation science approach to analyze barriers and facilitators to timely administration of FICB and select evidence-based interventions to enhance uptake. We conducted a qualitative study at a single centre using semistructured interviews and site observations. We interviewed 35 stakeholders including health care providers, managers, patients, and caregivers. We mapped barriers and facilitators to the Theoretical Domains Framework (TDF) and Consolidated Framework for Implementation Research (CFIR). We compared the rate and timeliness of FICB administration before and after evidence-based implementation strategies were applied. The study identified 18 barriers and 11 facilitators within seven themes of influences of FICB use: interpersonal relationships between health care professionals; clinician knowledge and skills related to FICB; roles, responsibilities, and processes for delivering FICB; perceptions on using FICB for pain; patient and caregiver perceptions on using FICB for pain; communication of hip fracture care between departments; and resources for delivering FICBs. We mapped the behaviour change domains to eight implementation strategies: restructure the environment, create and distribute educational materials, prepare patients to be active participants, perform audits and give feedback, use local opinion leaders, use champions, train staff on FICB procedures, and mandate change. We observed an increase in the rates of FICBs administered (48% vs 65%) and a decrease in the median time to administration (1.63 vs 0.81days). Our study explains why FICBs are underused and shows that the TDF and CFIR provide a framework to identify barriers and facilitators to FICB implementation. The mapped implementation strategies can guide institutions to improve use of FICB in hip fracture care.