diff --git a/provisioner/powershell/provisioner.go b/provisioner/powershell/provisioner.go
index ba0e2def3..3f0f0b9dd 100644
--- a/provisioner/powershell/provisioner.go
+++ b/provisioner/powershell/provisioner.go
@@ -347,7 +347,7 @@ func (p *Provisioner) createFlattenedEnvVars(elevated bool) (flattened string, e
 
 	// Split vars into key/value components
 	for _, envVar := range p.config.Vars {
-		keyValue := strings.Split(envVar, "=")
+		keyValue := strings.SplitN(envVar, "=", 2)
 
 		if len(keyValue) != 2 || keyValue[0] == "" {
 			err = errors.New(fmt.Sprintf("Shell provisioner environment variables must be in key=value format. Currently it is '%s'", envVar))