diff --git a/server/server.go b/server/server.go
index 7281c863..8e877d85 100644
--- a/server/server.go
+++ b/server/server.go
@@ -105,6 +105,15 @@ func NewServer(config Config) (*Server, error) {
 		gitlabClient = &vcs.GitlabClient{
 			Client: gitlab.NewClient(nil, config.GitlabToken),
 		}
+		// Ensure the BaseURL has /api/v4/ appended. We only care about the Scheme
+		// and Host. GH-229
+		u, err := url.Parse(config.GitlabHostname)
+		if err != nil {
+			return nil, errors.Wrap(err, "parsing GitLab hostname")
+		}
+		if err := gitlabClient.Client.SetBaseURL(fmt.Sprintf("%s://%s/api/v4/", u.Scheme, u.Host)); err != nil {
+			return nil, err
+		}
 	}
 	var webhooksConfig []webhooks.Config
 	for _, c := range config.Webhooks {