diff --git a/Libraries/LibWeb/IndexedDB/IDBObjectStore.cpp b/Libraries/LibWeb/IndexedDB/IDBObjectStore.cpp
index 4a5b4999236..aed485032f7 100644
--- a/Libraries/LibWeb/IndexedDB/IDBObjectStore.cpp
+++ b/Libraries/LibWeb/IndexedDB/IDBObjectStore.cpp
@@ -189,4 +189,37 @@ WebIDL::ExceptionOr<GC::Ref<IDBIndex>> IDBObjectStore::index(String const& name)
     return IDBIndex::create(realm(), *index, *this);
 }
 
+// https://w3c.github.io/IndexedDB/#dom-idbobjectstore-deleteindex
+WebIDL::ExceptionOr<void> IDBObjectStore::delete_index(String const& name)
+{
+    // 1. Let transaction be this’s transaction.
+    auto transaction = this->transaction();
+
+    // 2. Let store be this’s object store.
+    auto store = this->store();
+
+    // 3. If transaction is not an upgrade transaction, throw an "InvalidStateError" DOMException.
+    if (transaction->mode() != Bindings::IDBTransactionMode::Versionchange)
+        return WebIDL::InvalidStateError::create(realm(), "Transaction is not an upgrade transaction"_string);
+
+    // FIXME: 4. If store has been deleted, throw an "InvalidStateError" DOMException.
+
+    // 5. If transaction’s state is not active, then throw a "TransactionInactiveError" DOMException.
+    if (transaction->state() != IDBTransaction::TransactionState::Active)
+        return WebIDL::TransactionInactiveError::create(realm(), "Transaction is not active"_string);
+
+    // 6. Let index be the index named name in store if one exists, or throw a "NotFoundError" DOMException otherwise.
+    auto index = m_indexes.get(name);
+    if (!index.has_value())
+        return WebIDL::NotFoundError::create(realm(), "Index not found"_string);
+
+    // 7. Remove index from this’s index set.
+    m_indexes.remove(name);
+
+    // 8. Destroy index.
+    store->index_set().remove(name);
+
+    return {};
+}
+
 }
diff --git a/Libraries/LibWeb/IndexedDB/IDBObjectStore.h b/Libraries/LibWeb/IndexedDB/IDBObjectStore.h
index 0d3aac2a589..0fab61694be 100644
--- a/Libraries/LibWeb/IndexedDB/IDBObjectStore.h
+++ b/Libraries/LibWeb/IndexedDB/IDBObjectStore.h
@@ -42,6 +42,7 @@ public:
     WebIDL::ExceptionOr<GC::Ref<IDBIndex>> create_index(String const&, KeyPath, IDBIndexParameters options);
     [[nodiscard]] GC::Ref<HTML::DOMStringList> index_names();
     WebIDL::ExceptionOr<GC::Ref<IDBIndex>> index(String const&);
+    WebIDL::ExceptionOr<void> delete_index(String const&);
 
 protected:
     explicit IDBObjectStore(JS::Realm&, GC::Ref<ObjectStore>, GC::Ref<IDBTransaction>);
diff --git a/Libraries/LibWeb/IndexedDB/IDBObjectStore.idl b/Libraries/LibWeb/IndexedDB/IDBObjectStore.idl
index 947ecd6bcf5..90d51d3d686 100644
--- a/Libraries/LibWeb/IndexedDB/IDBObjectStore.idl
+++ b/Libraries/LibWeb/IndexedDB/IDBObjectStore.idl
@@ -23,7 +23,7 @@ interface IDBObjectStore {
     [FIXME, NewObject] IDBRequest openKeyCursor(optional any query, optional IDBCursorDirection direction = "next");
     IDBIndex index(DOMString name);
     [NewObject] IDBIndex createIndex(DOMString name, (DOMString or sequence<DOMString>) keyPath, optional IDBIndexParameters options = {});
-    [FIXME] undefined deleteIndex(DOMString name);
+    undefined deleteIndex(DOMString name);
 };
 
 dictionary IDBIndexParameters {