Vedolizumab blocks inflammatory activity within the gastrointestinal tract. Systematic reviews have demonstrated the efficacy of vedolizumab in ulcerative colitis and inflammatory bowel disease in general. This systematic review and meta-analysis summarises the current evidence of vedolizumab in the induction and maintenance of remission in Crohn's disease.To evaluate the benefits and harms of vedolizumab versus placebo for the induction and maintenance of remission in people with Crohn's disease.We used standard, extensive Cochrane search methods. The latest search date was 30 November 2022.We included randomised controlled trials (RCTs) and quasi-RCTs comparing vedolizumab to placebo for the induction or maintenance of remission in people with Crohn's disease.We used standard Cochrane methods. For induction studies, the primary outcome was 1. clinical remission, and secondary outcomes were rates of 2. clinical response, 3. adverse events, 4. serious adverse events, 5. surgery, 6. endoscopic remission and 7. endoscopic response. For maintenance studies, the primary outcome was 1. maintenance of clinical remission, and secondary outcomes were rates of 2. adverse events, 3. serious adverse events, 4. surgery, 5. endoscopic remission and 6. endoscopic response. We used GRADE to assess certainty of evidence.We analysed induction (4 trials, 1126 participants) and maintenance (3 trials, 894 participants) studies representing people across North America, Europe, Asia and Australasia separately. One maintenance trial administered subcutaneous vedolizumab whilst the other studies used the intravenous form. The mean age ranged between 32.6 and 38.6 years. Vedolizumab was superior to placebo for the induction of clinical remission (71 more per 1000 with clinical remission with vedolizumab; risk ratio (RR) 1.61, 95% confidence interval (CI) 1.20 to 2.17; number needed to treat for an additional beneficial outcome (NNTB) 13; 4 studies; high-certainty evidence) and superior to placebo for inducing clinical response (105 more per 1000 with clinical response with vedolizumab; RR 1.43, 95% CI 1.19 to 1.71; NNTB 8; 4 studies; high-certainty evidence). For the induction phase, vedolizumab may be equivalent to placebo for the development of serious adverse events (9 fewer serious adverse events per 1000 with vedolizumab; RR 0.91, 95% CI 0.62 to 1.33; 4 studies; low-certainty evidence) and probably equivalent to placebo for overall adverse events (6 fewer adverse events per 1000 with vedolizumab; RR 1.01, 95% CI 0.93 to 1.11; 4 studies; moderate-certainty evidence). Vedolizumab was superior to placebo for the maintenance of clinical remission (141 more per 1000 with maintenance of clinical remission with vedolizumab; RR 1.52, 95% CI 1.24 to 1.87; NNTB 7; 3 studies; high-certainty evidence). During the maintenance phase, vedolizumab may be equivalent to placebo for the development of serious adverse events (3 fewer serious adverse events per 1000 with vedolizumab; RR 0.98, 95% CI 0.68 to 1.39; 3 studies; low-certainty evidence) and probably equivalent to placebo for the development of overall adverse events (0 difference in adverse events per 1000; RR 1.00, 95% CI 0.94 to 1.07; 3 studies; moderate-certainty evidence).High-certainty data across four induction and three maintenance trials demonstrate that vedolizumab is superior to placebo in the induction and maintenance of remission in Crohn's disease. Overall adverse events are probably similar and serious adverse events may be similar between vedolizumab and placebo during both induction and maintenance phases of treatment. Head-to-head research comparing the efficacy and safety of vedolizumab to other biological therapies is required.