diff --git a/lib/src/op_walk.rs b/lib/src/op_walk.rs
index 3241f1163..bfc078363 100644
--- a/lib/src/op_walk.rs
+++ b/lib/src/op_walk.rs
@@ -207,13 +207,17 @@ impl PartialOrd for OperationByEndTime {
 
 /// Walks `head_ops` and their ancestors in reverse topological order.
 pub fn walk_ancestors(head_ops: &[Operation]) -> impl Iterator<Item = OpStoreResult<Operation>> {
+    // Emit the latest head first to stabilize the order.
+    let mut head_ops = head_ops
+        .iter()
+        .cloned()
+        .map(OperationByEndTime)
+        .collect_vec();
+    head_ops.sort_unstable_by(|op1, op2| op1.cmp(op2).reverse());
     // Lazily load operations based on timestamp-based heuristic. This works so long
     // as the operation history is mostly linear.
     dag_walk::topo_order_reverse_lazy_ok(
-        head_ops
-            .iter()
-            .map(|op| Ok(OperationByEndTime(op.clone())))
-            .collect_vec(),
+        head_ops.into_iter().map(Ok),
         |OperationByEndTime(op)| op.id().clone(),
         |OperationByEndTime(op)| op.parents().map_ok(OperationByEndTime).collect_vec(),
     )