diff --git a/catalog-spec/json-schema/catalog.json b/catalog-spec/json-schema/catalog.json
index 0f2c110f..c971c80b 100644
--- a/catalog-spec/json-schema/catalog.json
+++ b/catalog-spec/json-schema/catalog.json
@@ -22,6 +22,22 @@
         "type": {
           "title": "Type of STAC entity",
           "const": "Catalog"
+        },
+        "links": {
+          "title": "Links",
+          "type": "array",
+          "contains": {
+            "description": "A link to at least one `item` or `child` is REQUIRED in Catalogs.",
+            "type": "object",
+            "properties": {
+              "rel": {
+                "enum": [
+                  "child",
+                  "item"
+                ]
+              }
+            }
+          }
         }
       }
     }