diff --git a/distribution/changelog.txt b/distribution/changelog.txt
index de275a2a89..c9df1b69c6 100644
--- a/distribution/changelog.txt
+++ b/distribution/changelog.txt
@@ -1,9 +1,10 @@
 0.3.2+ (in development)
 ------------------------------------------------------------------------
 - Feature: [#13057] Make GameAction flags accessible by plugins.
-- Change: [#13346] Change FootpathScenery to FootpathAddition in all occurrences
-- Fix: [#13334] Uninitialised variables in CustomTabDesc
-- Fix: [#13342] Rename tabChange to onTabChange in WindowDesc interface
+- Feature: [#13376] Open custom window at specified tab.
+- Change: [#13346] Change FootpathScenery to FootpathAddition in all occurrences.
+- Fix: [#13334] Uninitialised variables in CustomTabDesc.
+- Fix: [#13342] Rename tabChange to onTabChange in WindowDesc interface.
 - Improved: [#12917] Changed peep movement so that they stay more spread out over the full width of single tile paths.
 
 0.3.2 (2020-11-01)
diff --git a/distribution/openrct2.d.ts b/distribution/openrct2.d.ts
index c10b2e7593..678e60e707 100644
--- a/distribution/openrct2.d.ts
+++ b/distribution/openrct2.d.ts
@@ -1866,6 +1866,7 @@ declare global {
         widgets?: Widget[];
         colours?: number[];
         tabs?: WindowTabDesc[];
+        tabIndex: number;
 
         onClose?: () => void;
         onUpdate?: () => void;
diff --git a/src/openrct2-ui/scripting/CustomWindow.cpp b/src/openrct2-ui/scripting/CustomWindow.cpp
index 5f6604dcc6..af7ccf415a 100644
--- a/src/openrct2-ui/scripting/CustomWindow.cpp
+++ b/src/openrct2-ui/scripting/CustomWindow.cpp
@@ -244,6 +244,7 @@ namespace OpenRCT2::Ui::Windows
         std::vector<CustomWidgetDesc> Widgets;
         std::vector<colour_t> Colours;
         std::vector<CustomTabDesc> Tabs;
+        std::optional<int32_t> TabIndex;
 
         // Event handlers
         DukValue OnClose;
@@ -271,6 +272,7 @@ namespace OpenRCT2::Ui::Windows
             result.MaxHeight = GetOptionalInt(desc["maxHeight"]);
             result.Title = language_convert_string(desc["title"].as_string());
             result.Id = GetOptionalInt(desc["id"]);
+            result.TabIndex = GetOptionalInt(desc["tabIndex"]);
 
             if (desc["widgets"].is_array())
             {
@@ -392,6 +394,9 @@ namespace OpenRCT2::Ui::Windows
         window->custom_info = new CustomWindowInfo(owner, desc);
         window->enabled_widgets = (1 << WIDX_CLOSE);
 
+        // Set window tab
+        window->page = desc.TabIndex.value_or(0);
+
         // Set window colours
         window->colours[0] = COLOUR_GREY;
         window->colours[1] = COLOUR_GREY;
diff --git a/src/openrct2/scripting/ScriptEngine.cpp b/src/openrct2/scripting/ScriptEngine.cpp
index 59c7b8addd..c9720a81d4 100644
--- a/src/openrct2/scripting/ScriptEngine.cpp
+++ b/src/openrct2/scripting/ScriptEngine.cpp
@@ -43,7 +43,7 @@
 using namespace OpenRCT2;
 using namespace OpenRCT2::Scripting;
 
-static constexpr int32_t OPENRCT2_PLUGIN_API_VERSION = 9;
+static constexpr int32_t OPENRCT2_PLUGIN_API_VERSION = 10;
 
 struct ExpressionStringifier final
 {