Tibial plateau fractures are difficult to treat and more likely complicated by subsequent surgical site infection (SSI). There is limited information about its characteristics and related risk factors for SSI. This study was designed as a prospective and multicentre one to address this issue. From July to 15 November in 2014, 235 patients with tibial plateau fractures were treated by open reduction and internal fixation (ORIF) and followed up with complete data. Twelve patients (5·1%, 12/235) developed SSI, with 2·1% for deep SSI and 3·0% for superficial SSI. Most of them (10/12) occurred during the hospital stays. The median occurrence time was 6 days after operation (range, 2–26 days). We use univariate and multivariate logistic regression models to investigate the potential risk factors. In the univariate analysis, open fracture, prolonged preoperative stay, smoking habitus and preoperative abnormal neutrophil (NEUT) count were significant risk factors for SSI occurrence. However, in multivariate analysis, only open fracture (OR, 3·31; 95%, 1·06–1·84) and current smoking status (OR, 5·68; 95% CI, 1·56–20·66) remained significant. We recommend that smoking cessation programme is introduced at the time of admission to the hospital and elaborative evaluation of fracture severity and soft‐tissue damage is performed with an aim of reducing the risk of post‐operative SSI.