diff --git a/api/errors/errors.go b/api/errors/errors.go
index 7ce7c5fe..2e033a53 100644
--- a/api/errors/errors.go
+++ b/api/errors/errors.go
@@ -57,6 +57,7 @@ const (
 	ErrInvalidCopyDest
 	ErrInvalidPolicyDocument
 	ErrInvalidObjectState
+	ErrMalformedACL
 	ErrMalformedXML
 	ErrMissingContentLength
 	ErrMissingContentMD5
@@ -456,6 +457,12 @@ var errorCodes = errorCodeMap{
 		Description:    "The requested range is not satisfiable",
 		HTTPStatusCode: http.StatusRequestedRangeNotSatisfiable,
 	},
+	ErrMalformedACL: {
+		ErrCode:        ErrMalformedACL,
+		Code:           "MalformedACLError",
+		Description:    "The ACL that you provided was not well formed or did not validate against our published schema.",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
 	ErrMalformedXML: {
 		ErrCode:        ErrMalformedXML,
 		Code:           "MalformedXML",
diff --git a/api/handler/put.go b/api/handler/put.go
index 9775de52..c3776f79 100644
--- a/api/handler/put.go
+++ b/api/handler/put.go
@@ -744,7 +744,7 @@ func parseCannedACL(header http.Header) (string, error) {
 		return acl, nil
 	}
 
-	return "", fmt.Errorf("unknown acl: %s", acl)
+	return "", apierr.GetAPIErrorWithError(apierr.ErrMalformedACL, fmt.Errorf("unknown acl: %s", acl))
 }
 
 func (h *handler) CreateBucketHandler(w http.ResponseWriter, r *http.Request) {