Objective: To explore the optimal timing of chemoimmunotherapy combined with radiotherapy for oligometastatic esophageal squamous carcinoma and analyze the prognostic factors. Methods: 71 patients with oligometastatic esophageal squamous carcinoma who received chemoimmunotherapy combined with radiotherapy were selected as research subjects, and were divided into three groups according to the timing of radiotherapy relative to chemoimmunotherapy: The first radiotherapy group (receiving radiotherapy before chemoimmunotherapy, n = 21), The synchronous radiotherapy group (receiving radiotherapy within four cycles from the start of chemoimmunotherapy, n = 29), The sequential radiotherapy group (receiving radiotherapy after four cycles from the start of chemoimmunotherapy, n = 21). Clinical efficacy [disease control rate (DCR), progression-free survival (PFS), overall survival (OS)] and incidence of adverse reactions were compared among the three groups. According to the neutrophil-to-lymphocyte ratio (NLR), patients were further divided into a low NLR group (NLR 2.33, n = 39), and their overall survival (OS) was compared. Univariate and multivariate Cox regression analyses were conducted to identify factors affecting the prognosis of patients with oligometastatic esophageal cancer. Results: The DCR for the first radiotherapy group, synchronous radiotherapy group, and sequential radiotherapy group were 33.3%, 44.8%, and 52.4%, respectively. There was no statistically significant difference in DCR among the three groups (P > 0.05). The median PFS for the first, synchronous, and sequential radiotherapy groups were 11.9, 17.6, and 17.5 months, respectively, with no statistically significant difference among the three groups (P > 0.05). The median OS for the first radiotherapy group, synchronous radiotherapy group, and sequential radiotherapy group was 18.4 months (95% CI: 13.1–23.7), 21.7 months (95% CI: 17.8–25.7), and 16.5 months (95% CI: 9.9–23.1), respectively. The differences in OS among the three groups were statistically significant (P 0.05). The OS for the low NLR group and the high NLR group was 23.3 months (95% CI: 19.6–27.0) and 16.6 months (95% CI: 15.1–18.1), respectively (P < 0.05). Both univariate and multivariate analyses indicated that NLR was an independent prognostic factor for patients with oligometastatic esophageal cancer (HR = 4.17, 95% CI: 2.17–8.00, P < 0.05). Conclusion: For patients with oligometastatic esophageal squamous carcinoma, initiating radiotherapy within four weeks of starting chemoimmunotherapy (i.e., concurrent chemoimmunotherapy and radiotherapy) prolongs overall survival without increasing treatment-related adverse effects. NLR is a valuable prognostic marker in this setting, and a high pretreatment NLR suggests a poorer prognosis.