diff --git a/plumbing/protocol/packp/advrefs.go b/plumbing/protocol/packp/advrefs.go
index 208e9b1ca..bfb9f798a 100644
--- a/plumbing/protocol/packp/advrefs.go
+++ b/plumbing/protocol/packp/advrefs.go
@@ -203,11 +203,11 @@ func (a *AdvRefs) IsEmpty() bool {
 // MakeReferenceSlice returns a sorted slice with all the references, their
 // peeled values, and symrefs.
 func (a *AdvRefs) MakeReferenceSlice() ([]*plumbing.Reference, error) {
-	allRefs := make([]*plumbing.Reference, 0)
 	refs, err := a.AllReferences()
 	if err != nil {
 		return nil, err
 	}
+	allRefs := make([]*plumbing.Reference, 0, len(refs))
 
 	for _, ref := range refs {
 		allRefs = append(allRefs, ref)