Background In advanced biliary tract carcinoma (BTC), the prognosis is very poor, and the overall survival is less than 1 year. This study aimed to determine the effect of neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), C-reactive protein (CRP)/albumin ratio (CAR), and prognostic nutritional index (PNI) on the survival of BTC patients treated with gemcitabine/oxaliplatin (GEMOX) regimen. Methods Data of 53 patients with advanced BTC were evaluated retrospectively. Association between inflammatory markers and 6-month PFS and 12-month OS were compared by the log-rank test. The optimal cutoff values were determined by a receiver operating characteristic (ROC) curve analysis. NLR, dNLR, CAR, and PNI were grouped based on cutoff points 1.95, 1.15, 0.57, and 33, respectively. Univariate and multivariate analyses were used to assess their prognostic values for survival. Results Lower dNLR (< 1.15) was prognostic for higher 6-month PFS and 12-month OS rates, while lower NLR (< 1.95) was prognostic for higher 6-month PFS rates only. CAR and PNI did not have statistically significant effects on survival. Conclusions Pretreatment dNLR and NLR values in advanced BTC can be used as predictive markers for survival in patients undergoing the GEMOX regimen.