diff --git a/Libraries/LibWeb/IndexedDB/IDBIndex.cpp b/Libraries/LibWeb/IndexedDB/IDBIndex.cpp
index a62ea6e5e31..86cb1b9be33 100644
--- a/Libraries/LibWeb/IndexedDB/IDBIndex.cpp
+++ b/Libraries/LibWeb/IndexedDB/IDBIndex.cpp
@@ -71,14 +71,16 @@ WebIDL::ExceptionOr<void> IDBIndex::set_name(String const& value)
         return {};
 
     // 8. If an index named name already exists in index’s object store, throw a "ConstraintError" DOMException.
-    for (auto const& existing_index : m_object_store_handle->index_set()) {
-        if (existing_index->name() == name)
-            return WebIDL::ConstraintError::create(realm, "An index with the given name already exists"_string);
-    }
+    if (index->object_store()->index_set().contains(name))
+        return WebIDL::ConstraintError::create(realm, "An index with the given name already exists"_string);
 
     // 9. Set index’s name to name.
     index->set_name(name);
 
+    // NOTE: Update the key in the map so it still matches the name
+    auto old_value = m_object_store_handle->index_set().take(m_name).release_value();
+    m_object_store_handle->index_set().set(name, old_value);
+
     // 10. Set this’s name to name.
     m_name = name;
 
diff --git a/Libraries/LibWeb/IndexedDB/IDBObjectStore.cpp b/Libraries/LibWeb/IndexedDB/IDBObjectStore.cpp
index fbbcbe1c205..35f7ea24f46 100644
--- a/Libraries/LibWeb/IndexedDB/IDBObjectStore.cpp
+++ b/Libraries/LibWeb/IndexedDB/IDBObjectStore.cpp
@@ -9,6 +9,7 @@
 #include <LibWeb/Bindings/IDBObjectStorePrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/HTML/EventNames.h>
+#include <LibWeb/IndexedDB/IDBIndex.h>
 #include <LibWeb/IndexedDB/IDBObjectStore.h>
 
 namespace Web::IndexedDB {
@@ -41,6 +42,7 @@ void IDBObjectStore::visit_edges(Visitor& visitor)
     Base::visit_edges(visitor);
     visitor.visit(m_store);
     visitor.visit(m_transaction);
+    visitor.visit(m_indexes);
 }
 
 // https://w3c.github.io/IndexedDB/#dom-idbobjectstore-keypath
@@ -101,4 +103,54 @@ WebIDL::ExceptionOr<void> IDBObjectStore::set_name(String const& value)
     return {};
 }
 
+// https://w3c.github.io/IndexedDB/#dom-idbobjectstore-createindex
+WebIDL::ExceptionOr<GC::Ref<IDBIndex>> IDBObjectStore::create_index(String const& name, KeyPath key_path, IDBIndexParameters options)
+{
+    auto& realm = this->realm();
+
+    // 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 while creating index"_string);
+
+    // 6. If an index named name already exists in store, throw a "ConstraintError" DOMException.
+    if (store->index_set().contains(name))
+        return WebIDL::ConstraintError::create(realm, "An index with the given name already exists"_string);
+
+    // 7. If keyPath is not a valid key path, throw a "SyntaxError" DOMException.
+    if (!is_valid_key_path(key_path))
+        return WebIDL::SyntaxError::create(realm, "Key path is not valid"_string);
+
+    // 8. Let unique be options’s unique member.
+    auto unique = options.unique;
+
+    // 9. Let multiEntry be options’s multiEntry member.
+    auto multi_entry = options.multi_entry;
+
+    // 10. If keyPath is a sequence and multiEntry is true, throw an "InvalidAccessError" DOMException.
+    if (key_path.has<Vector<String>>() && multi_entry)
+        return WebIDL::InvalidAccessError::create(realm, "Key path is a sequence and multiEntry is true"_string);
+
+    // 11. Let index be a new index in store.
+    //     Set index’s name to name, key path to keyPath, unique flag to unique, and multiEntry flag to multiEntry.
+    auto index = Index::create(realm, store, name, key_path, unique, multi_entry);
+
+    // 12. Add index to this's index set.
+    this->index_set().set(name, index);
+
+    // 13. Return a new index handle associated with index and this.
+    return IDBIndex::create(realm, index, *this);
+}
+
 }
diff --git a/Libraries/LibWeb/IndexedDB/IDBObjectStore.h b/Libraries/LibWeb/IndexedDB/IDBObjectStore.h
index c22fd5081ee..df6e0f03efb 100644
--- a/Libraries/LibWeb/IndexedDB/IDBObjectStore.h
+++ b/Libraries/LibWeb/IndexedDB/IDBObjectStore.h
@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <AK/HashMap.h>
 #include <LibGC/Heap.h>
 #include <LibWeb/Bindings/PlatformObject.h>
 #include <LibWeb/IndexedDB/IDBTransaction.h>
@@ -13,6 +14,11 @@
 
 namespace Web::IndexedDB {
 
+struct IDBIndexParameters {
+    bool unique { false };
+    bool multi_entry { false };
+};
+
 // https://w3c.github.io/IndexedDB/#object-store-interface
 // https://w3c.github.io/IndexedDB/#object-store-handle-construct
 class IDBObjectStore : public Bindings::PlatformObject {
@@ -23,14 +29,17 @@ public:
     virtual ~IDBObjectStore() override;
     [[nodiscard]] static GC::Ref<IDBObjectStore> create(JS::Realm&, GC::Ref<ObjectStore>, GC::Ref<IDBTransaction>);
 
-    JS::Value key_path() const;
-    GC::Ref<IDBTransaction> transaction() const { return m_transaction; }
-
     // https://w3c.github.io/IndexedDB/#dom-idbobjectstore-autoincrement
     // The autoIncrement getter steps are to return true if this’s object store has a key generator, and false otherwise.
     bool auto_increment() const { return m_store->key_generator().has_value(); }
+    JS::Value key_path() const;
     String name() const { return m_name; }
     WebIDL::ExceptionOr<void> set_name(String const& value);
+    GC::Ref<IDBTransaction> transaction() const { return m_transaction; }
+    GC::Ref<ObjectStore> store() const { return m_store; }
+    AK::HashMap<String, GC::Ref<Index>>& index_set() { return m_indexes; }
+
+    WebIDL::ExceptionOr<GC::Ref<IDBIndex>> create_index(String const&, KeyPath, IDBIndexParameters options);
 
 protected:
     explicit IDBObjectStore(JS::Realm&, GC::Ref<ObjectStore>, GC::Ref<IDBTransaction>);
@@ -44,6 +53,9 @@ private:
 
     // An object store handle has a name, which is initialized to the name of the associated object store when the object store handle is created.
     String m_name;
+
+    // An object store handle has an index set
+    AK::HashMap<String, GC::Ref<Index>> m_indexes;
 };
 
 }
diff --git a/Libraries/LibWeb/IndexedDB/IDBObjectStore.idl b/Libraries/LibWeb/IndexedDB/IDBObjectStore.idl
index 66dd3ef722d..4af455b4102 100644
--- a/Libraries/LibWeb/IndexedDB/IDBObjectStore.idl
+++ b/Libraries/LibWeb/IndexedDB/IDBObjectStore.idl
@@ -22,7 +22,7 @@ interface IDBObjectStore {
     [FIXME, NewObject] IDBRequest openCursor(optional any query, optional IDBCursorDirection direction = "next");
     [FIXME, NewObject] IDBRequest openKeyCursor(optional any query, optional IDBCursorDirection direction = "next");
     [FIXME] IDBIndex index(DOMString name);
-    [FIXME, NewObject] IDBIndex createIndex(DOMString name, (DOMString or sequence<DOMString>) keyPath, optional IDBIndexParameters options = {});
+    [NewObject] IDBIndex createIndex(DOMString name, (DOMString or sequence<DOMString>) keyPath, optional IDBIndexParameters options = {});
     [FIXME] undefined deleteIndex(DOMString name);
 };
 
diff --git a/Libraries/LibWeb/IndexedDB/Internal/Index.cpp b/Libraries/LibWeb/IndexedDB/Internal/Index.cpp
index 38ea6e1e27e..d347f1dd49f 100644
--- a/Libraries/LibWeb/IndexedDB/Internal/Index.cpp
+++ b/Libraries/LibWeb/IndexedDB/Internal/Index.cpp
@@ -25,7 +25,7 @@ Index::Index(GC::Ref<ObjectStore> store, String name, KeyPath const& key_path, b
     , m_multi_entry(multi_entry)
     , m_key_path(key_path)
 {
-    store->add_index(*this);
+    store->index_set().set(name, *this);
 }
 
 void Index::visit_edges(Visitor& visitor)
@@ -39,4 +39,13 @@ void Index::visit_edges(Visitor& visitor)
     }
 }
 
+void Index::set_name(String name)
+{
+    // NOTE: Update the key in the map so it still matches the name
+    auto old_value = m_object_store->index_set().take(m_name).release_value();
+    m_object_store->index_set().set(name, old_value);
+
+    m_name = move(name);
+}
+
 }
diff --git a/Libraries/LibWeb/IndexedDB/Internal/Index.h b/Libraries/LibWeb/IndexedDB/Internal/Index.h
index e984ffbc1b4..6296c8b805c 100644
--- a/Libraries/LibWeb/IndexedDB/Internal/Index.h
+++ b/Libraries/LibWeb/IndexedDB/Internal/Index.h
@@ -31,7 +31,7 @@ public:
     [[nodiscard]] static GC::Ref<Index> create(JS::Realm&, GC::Ref<ObjectStore>, String, KeyPath const&, bool, bool);
     virtual ~Index();
 
-    void set_name(String name) { m_name = move(name); }
+    void set_name(String name);
     [[nodiscard]] String name() const { return m_name; }
     [[nodiscard]] bool unique() const { return m_unique; }
     [[nodiscard]] bool multi_entry() const { return m_multi_entry; }
diff --git a/Libraries/LibWeb/IndexedDB/Internal/ObjectStore.h b/Libraries/LibWeb/IndexedDB/Internal/ObjectStore.h
index d7f400e37bc..810c33eb8fb 100644
--- a/Libraries/LibWeb/IndexedDB/Internal/ObjectStore.h
+++ b/Libraries/LibWeb/IndexedDB/Internal/ObjectStore.h
@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <AK/HashMap.h>
 #include <AK/Optional.h>
 #include <AK/String.h>
 #include <AK/Variant.h>
@@ -37,12 +38,10 @@ public:
     bool uses_inline_keys() const { return m_key_path.has_value(); }
     bool uses_out_of_line_keys() const { return !m_key_path.has_value(); }
     Optional<KeyGenerator> key_generator() const { return m_key_generator; }
+    AK::HashMap<String, GC::Ref<Index>>& index_set() { return m_indexes; }
 
     GC::Ref<Database> database() const { return m_database; }
 
-    void add_index(GC::Ref<Index> index) { m_indexes.append(index); }
-    ReadonlySpan<GC::Ref<Index>> index_set() const { return m_indexes; }
-
 protected:
     virtual void visit_edges(Visitor&) override;
 
@@ -53,7 +52,7 @@ private:
     GC::Ref<Database> m_database;
 
     // AD-HOC: An Index has referenced ObjectStores, we also need the reverse mapping
-    Vector<GC::Ref<Index>> m_indexes;
+    AK::HashMap<String, GC::Ref<Index>> m_indexes;
 
     // An object store has a name, which is a name. At any one time, the name is unique within the database to which it belongs.
     String m_name;