Objectives To report the incidence of and risk factors for development of recurrent secondary septic peritonitis (RSSP) in dogs. To report the outcome of dogs treated surgically for RSSP. Design Retrospective study. Setting University teaching hospital. Animals One hundred forty‐nine client‐owned dogs treated surgically for secondary septic peritonitis (SSP). Interventions None. Measurements and Results The medical records database was searched for dogs that underwent surgery to treat SSP. Of 149 dogs that met the inclusion criteria, 15 (10.1%) dogs developed RSSP following surgery and 134 (89.9%) did not. Dogs with RSSP had significantly lower albumin prior to the first surgery to treat secondary septic peritonitis (SPsx1) (median 18 g/L [1.8 g/dL] vs 22 g/L [2.2 g/dL], P = 0.005) and significantly higher PCV prior to SPsx1 (median 52% vs 45%, P = 0.028). Dogs with septic peritonitis of gastrointestinal (GI) origin were significantly more likely to develop recurrent peritonitis than those with sepsis from a non‐GI source (odds ratio [OR], 4.4, 95% CI: 0.95–20, P = 0.041). Of dogs with sepsis of GI origin, those with sepsis due to a foreign body were significantly more likely to develop RSSP than those with GI sepsis from a non‐foreign body cause (OR, 7.2, 95% CI: 1.6–43, P = 0.0018). Of the 15 dogs in the RSSP group, 8 were euthanized without further treatment. Relaparotomy was performed in the remaining 7 cases; 3 of these (42.9%) survived. Conclusions There was a 10.1% rate of RSSP following SPsx1. Preoperative albumin was significantly lower and preoperative PCV was significantly higher in dogs that developed recurrence. Dogs with GI sepsis were at increased risk of recurrence and, among dogs with GI sepsis, the presence of a foreign body was an additional risk factor for recurrence.