Tibial plateau fractures, which are intra-articular injuries of the knee joint, are often difficult to treat and have a high complication rate, including early-onset osteoarthritis. The most common treatment for complex tibial plateau fractures is surgical fixation. Additionally, orthopaedic surgeons often use bone defect fillers to address bone defects caused by the injury. Currently, there is no consensus on the best method of fixation and on whether bone defect fillers are necessary. To assess the benefits and harms of different surgical interventions and bone defect fillers for treating tibial plateau fractures. We searched CENTRAL, MEDLINE, Embase, and trial registries up to March 2023. We also searched conference proceedings and the grey literature. We included randomised controlled trials (RCTs) and quasi-RCTs comparing surgical interventions for treating tibial plateau fractures and different types of filler for bone defects. Two review authors independently screened search results, selected studies, extracted data, and assessed risk of bias. We calculated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) or standardised mean differences (SMDs) for continuous outcomes, with 95% confidence intervals (CIs). Our primary outcomes (and the specific measures we considered most relevant) were generic quality of life (general health score in the 36-item Short-Form Health Survey (SF-36)), patient-reported lower limb function (Hospital for Special Surgery (HSS) score), and adverse events (frequency of unplanned reoperation). We used GRADE to assess the certainty of evidence. We included 15 trials in the review, with a total of 948 adult participants. Nine trials compared different types of fixation, and six trials evaluated different types of bone graft substitutes. All 15 trials were small and at high risk of bias. We considered most available evidence to be of very low certainty, meaning we have very little confidence in the results. Only limited pooling was possible. One trial compared circular fixation combined with insertion of percutaneous screws (hybrid fixation) versus standard open reduction and internal fixation (ORIF) in 82 people with open or closed Schatzker types V or VI tibial plateau fractures. At 24 months' follow-up, hybrid fixation compared with ORIF may have little or no effect on SF-36 general health score (MD 6 points higher, 95% CI 7.7 points lower to 19.7 points higher; 66 participants), patient-reported lower limb function according to the HSS score (MD 7 points higher, 95% CI 2.4 points lower to 16.4 points higher; 66 participants), or frequency of unplanned reoperation (RR 0.78, 95% CI 0.45 to 1.32; 83 fractures (82 participants)). However, the evidence for all three outcomes is very uncertain. Three trials (with 242 participants) compared single-plating ORIF versus double-plating ORIF. There may be little to know difference in patient-reported lower limb function (HSS score) at 24 months' follow-up in people who undergo single-plating ORIF compared with those who undergo double-plating ORIF (MD 0.2 points higher, 95% CI 2.12 points lower to 2.52 points higher; 1 study, 84 participants), but the evidence is very uncertain. There were no data for quality of life or unplanned reoperation at 24 months' follow-up. Six trials (including 368 participants) compared bone substitute versus autologous bone graft (autograft) for managing bone defects. No trials reported SF-36 general health score, HSS score, or frequency of unplanned reoperation at 24 months' follow-up. There is insufficient evidence to ascertain the best method of fixation or the best method of addressing bone defects during surgery in people with tibial plateau fractures. Further well-designed RCTs with larger sample sizes are warranted.