Objective. Delirium is a temporary neuropsychiatric syndrome characterized by fluctuations in cognition and attention. Delirium is one of the most common complications seen in old individuals after orthopaedic surgery. With a high incidence, the clinical picture of delirium increases the length of hospital stay and increases healthcare-related costs. This study has aimed to systematically review the national and international studies that investigated the risk factors leading to delirium in geriatric patients after orthopaedic surgery and to perform a meta-analysis using the data reported by those studies. Materials and Methods. A preliminary literature review was performed on six databases. The following English keyword combinations were used including 'Orthopaedic Surgery', 'Geriatrics', 'Elderly', and 'Delirium'. The results of trials were evaluated with random or fixed effect model according to the heterogeneity. Statistical evaluation was performed by using Comprehensive Meta Analysis version 3 programme. Results. The total sample size of the studies included in the analysis was 892. In geriatric patients; who had undergone orthopaedic surgery and developed delirium, the random-effects model revealed a high-level, in the positive direction, and statistically significant (p<0.05) overall effect size of 5.21 (CI; 1.33-20.33) for gender, 1.33 (CI; 0.58-2.06) for age, 11.30 (CI; 4.70-27.12 for polypharmacy, and a low-level, in the positive direction, and statistically significant (p<0.05) overall effect size of 0.12 (CI; 0.05-0.27) for mini-mental state examination as the risk factors leading to the development of delirium. Conclusions. Advanced age, female gender, polypharmacy, and a mini-mental state examination score of 17-23 are major risk factors for the development of delirium after orthopaedic surgery.