diff --git a/core/object/script_language.h b/core/object/script_language.h
index 3ddfbb3e7d35..cc02d23a4351 100644
--- a/core/object/script_language.h
+++ b/core/object/script_language.h
@@ -363,6 +363,7 @@ class ScriptLanguage : public Object {
 
 	virtual Error lookup_code(const String &p_code, const String &p_symbol, const String &p_path, Object *p_owner, LookupResult &r_result) { return ERR_UNAVAILABLE; }
 
+	virtual String format_code(const String &p_code) { return p_code; }
 	virtual void auto_indent_code(String &p_code, int p_from_line, int p_to_line) const = 0;
 	virtual void add_global_constant(const StringName &p_variable, const Variant &p_value) = 0;
 	virtual void add_named_global_constant(const StringName &p_name, const Variant &p_value) {}
diff --git a/editor/plugins/SCsub b/editor/plugins/SCsub
index 4b6abf18f946..1ca3ba8409f4 100644
--- a/editor/plugins/SCsub
+++ b/editor/plugins/SCsub
@@ -4,5 +4,8 @@ Import("env")
 
 env.add_source_files(env.editor_sources, "*.cpp")
 
+if env["tests"]:
+    env.Append(CPPDEFINES=["TESTS_ENABLED"])
+
 SConscript("gizmos/SCsub")
 SConscript("tiles/SCsub")
diff --git a/editor/plugins/script_editor_plugin.h b/editor/plugins/script_editor_plugin.h
index 8e82d606052e..0e1cf87b5809 100644
--- a/editor/plugins/script_editor_plugin.h
+++ b/editor/plugins/script_editor_plugin.h
@@ -175,6 +175,7 @@ class ScriptEditorBase : public VBoxContainer {
 	virtual void clear_executing_line() = 0;
 	virtual void trim_trailing_whitespace() = 0;
 	virtual void trim_final_newlines() = 0;
+	virtual void format_code() = 0;
 	virtual void insert_final_newline() = 0;
 	virtual void convert_indent() = 0;
 	virtual void ensure_focus() = 0;
diff --git a/editor/plugins/script_text_editor.cpp b/editor/plugins/script_text_editor.cpp
index 7e8fba8b9ecc..7cd532faa40a 100644
--- a/editor/plugins/script_text_editor.cpp
+++ b/editor/plugins/script_text_editor.cpp
@@ -438,6 +438,42 @@ void ScriptTextEditor::trim_trailing_whitespace() {
 	code_editor->trim_trailing_whitespace();
 }
 
+void ScriptTextEditor::format_code() {
+#ifdef TESTS_ENABLED
+	CodeEdit *tx = code_editor->get_text_editor();
+	const String original = tx->get_text();
+	Ref<Script> scr = script;
+
+	const String formatted_code = scr->get_language()->format_code(original);
+
+	if (formatted_code == original) {
+		return;
+	}
+
+	const Vector<String> original_lines = original.split("\n");
+	const Vector<String> formatted_lines = formatted_code.split("\n");
+
+	tx->begin_complex_operation();
+
+	const int end = MIN(original_lines.size(), formatted_lines.size());
+	for (int i = 0; i < end; ++i) {
+		if (original_lines[i] == formatted_lines[i]) {
+			continue;
+		}
+		tx->set_line(i, formatted_lines[i]);
+	}
+	if (original_lines.size() > formatted_lines.size()) {
+		tx->remove_text(formatted_lines.size() - 1, 0, original_lines.size() - 1, tx->get_line_width(original_lines.size() - 1));
+	} else if (original_lines.size() < formatted_lines.size()) {
+		Vector remainder{ tx->get_line(tx->get_line_count() - 1) };
+		remainder.append_array(formatted_lines.slice(tx->get_line_count()));
+		tx->set_line(tx->get_line_count() - 1, String("\n").join(remainder));
+	}
+
+	tx->end_complex_operation();
+#endif
+}
+
 void ScriptTextEditor::trim_final_newlines() {
 	code_editor->trim_final_newlines();
 }
@@ -1440,6 +1476,11 @@ void ScriptTextEditor::_edit_option(int p_op) {
 		case EDIT_TRIM_FINAL_NEWLINES: {
 			trim_final_newlines();
 		} break;
+#ifdef TESTS_ENABLED
+		case EDIT_FORMAT_CODE: {
+			format_code();
+		} break;
+#endif
 		case EDIT_CONVERT_INDENT_TO_SPACES: {
 			code_editor->set_indent_using_spaces(true);
 			convert_indent();
@@ -2316,6 +2357,9 @@ void ScriptTextEditor::_enable_code_editor() {
 	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("ui_text_completion_query"), EDIT_COMPLETE);
 	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("script_text_editor/trim_trailing_whitespace"), EDIT_TRIM_TRAILING_WHITESAPCE);
 	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("script_text_editor/trim_final_newlines"), EDIT_TRIM_FINAL_NEWLINES);
+#ifdef TESTS_ENABLED
+	edit_menu->get_popup()->add_shortcut(ED_SHORTCUT("script_text_editor/format_code", TTR("Format Code"), KeyModifierMask::SHIFT | KeyModifierMask::ALT | Key::F), EDIT_FORMAT_CODE);
+#endif
 	{
 		PopupMenu *sub_menu = memnew(PopupMenu);
 		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/convert_indent_to_spaces"), EDIT_CONVERT_INDENT_TO_SPACES);
diff --git a/editor/plugins/script_text_editor.h b/editor/plugins/script_text_editor.h
index 7aa0726479f5..5531b01802f1 100644
--- a/editor/plugins/script_text_editor.h
+++ b/editor/plugins/script_text_editor.h
@@ -119,6 +119,7 @@ class ScriptTextEditor : public ScriptEditorBase {
 		EDIT_AUTO_INDENT,
 		EDIT_TRIM_TRAILING_WHITESAPCE,
 		EDIT_TRIM_FINAL_NEWLINES,
+		EDIT_FORMAT_CODE,
 		EDIT_CONVERT_INDENT_TO_SPACES,
 		EDIT_CONVERT_INDENT_TO_TABS,
 		EDIT_TOGGLE_COMMENT,
@@ -230,6 +231,7 @@ class ScriptTextEditor : public ScriptEditorBase {
 	virtual void ensure_focus() override;
 	virtual void trim_trailing_whitespace() override;
 	virtual void trim_final_newlines() override;
+	virtual void format_code() override;
 	virtual void insert_final_newline() override;
 	virtual void convert_indent() override;
 	virtual void tag_saved_version() override;
diff --git a/editor/plugins/text_editor.h b/editor/plugins/text_editor.h
index b6c203f2a284..32a764cd7edd 100644
--- a/editor/plugins/text_editor.h
+++ b/editor/plugins/text_editor.h
@@ -135,6 +135,7 @@ class TextEditor : public ScriptEditorBase {
 	virtual void clear_executing_line() override;
 	virtual void trim_trailing_whitespace() override;
 	virtual void trim_final_newlines() override;
+	virtual void format_code() override {}
 	virtual void insert_final_newline() override;
 	virtual void convert_indent() override;
 	virtual void ensure_focus() override;
diff --git a/main/main.cpp b/main/main.cpp
index fa50a3039f43..f6b832d8b66d 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -87,6 +87,7 @@
 #endif // _3D_DISABLED
 
 #ifdef TESTS_ENABLED
+#include "modules/gdscript/gdscript_formatter.h"
 #include "tests/test_main.h"
 #endif
 
@@ -634,6 +635,9 @@ void Main::print_help(const char *p_binary) {
 	print_help_option("-s, --script <script>", "Run a script.\n");
 	print_help_option("--main-loop <main_loop_name>", "Run a MainLoop specified by its global class name.\n");
 	print_help_option("--check-only", "Only parse for errors and quit (use with --script).\n");
+#ifdef TESTS_ENABLED
+	print_help_option("--format", "Format the file in-place or (if used with --check-only) check if file is formatted correctly. This option must be used with --script.\n");
+#endif
 #ifdef TOOLS_ENABLED
 	print_help_option("--import", "Starts the editor, waits for any resources to be imported, and then quits.\n", CLI_OPTION_AVAILABILITY_EDITOR);
 	print_help_option("--export-release <preset> <path>", "Export the project in release mode using the given preset and output path. The preset name should match one defined in \"export_presets.cfg\".\n", CLI_OPTION_AVAILABILITY_EDITOR);
@@ -3465,6 +3469,9 @@ int Main::start() {
 	String script;
 	String main_loop_type;
 	bool check_only = false;
+#ifdef TESTS_ENABLED
+	bool format = false;
+#endif
 
 #ifdef TOOLS_ENABLED
 	String doc_tool_path;
@@ -3493,6 +3500,10 @@ int Main::start() {
 		// Designed to override and pass arguments to the unit test handler.
 		if (E->get() == "--check-only") {
 			check_only = true;
+#ifdef TESTS_ENABLED
+		} else if (E->get() == "--format") {
+			format = true;
+#endif
 #ifdef TOOLS_ENABLED
 		} else if (E->get() == "--no-docbase") {
 			gen_flags.set_flag(DocTools::GENERATE_FLAG_SKIP_BASIC_TYPES);
@@ -3751,6 +3762,24 @@ int Main::start() {
 		Ref<Script> script_res = ResourceLoader::load(script);
 		ERR_FAIL_COND_V_MSG(script_res.is_null(), EXIT_FAILURE, "Can't load script: " + script);
 
+#ifdef TESTS_ENABLED
+		if (format) {
+			if (check_only) {
+				GDScriptFormatter formatter;
+				String formattedCode;
+				if (formatter.format(script_res->get_source_code(), formattedCode) != OK)
+					return EXIT_FAILURE;
+				if (script_res->get_source_code() != formattedCode) {
+					print_line("Would reformat the script."); // TODO: Print diff.
+					return EXIT_FAILURE;
+				}
+				return EXIT_SUCCESS;
+			} else {
+				ERR_FAIL_V_MSG(EXIT_FAILURE, "Formatting in-place is not supported yet");
+			}
+		}
+#endif
+
 		if (check_only) {
 			return script_res->is_valid() ? EXIT_SUCCESS : EXIT_FAILURE;
 		}
diff --git a/modules/gdscript/gdscript.h b/modules/gdscript/gdscript.h
index 9bb39aac0f7e..7ea91a7ff33c 100644
--- a/modules/gdscript/gdscript.h
+++ b/modules/gdscript/gdscript.h
@@ -587,6 +587,7 @@ class GDScriptLanguage : public ScriptLanguage {
 	virtual Error lookup_code(const String &p_code, const String &p_symbol, const String &p_path, Object *p_owner, LookupResult &r_result) override;
 #endif
 	virtual String _get_indentation() const;
+	virtual String format_code(const String &p_code) override;
 	virtual void auto_indent_code(String &p_code, int p_from_line, int p_to_line) const override;
 	virtual void add_global_constant(const StringName &p_variable, const Variant &p_value) override;
 	virtual void add_named_global_constant(const StringName &p_name, const Variant &p_value) override;
diff --git a/modules/gdscript/gdscript_editor.cpp b/modules/gdscript/gdscript_editor.cpp
index cf1cd55355c3..8836f8602436 100644
--- a/modules/gdscript/gdscript_editor.cpp
+++ b/modules/gdscript/gdscript_editor.cpp
@@ -32,6 +32,7 @@
 
 #include "gdscript_analyzer.h"
 #include "gdscript_compiler.h"
+#include "gdscript_formatter.h"
 #include "gdscript_parser.h"
 #include "gdscript_tokenizer.h"
 #include "gdscript_utility_functions.h"
@@ -3554,6 +3555,18 @@ String GDScriptLanguage::_get_indentation() const {
 	return "\t";
 }
 
+String GDScriptLanguage::format_code(const String &p_code) {
+#ifdef TESTS_ENABLED
+	GDScriptFormatter formatter;
+	String formatted_code;
+	Error err = formatter.format(p_code, formatted_code);
+	if (err == OK) {
+		return formatted_code;
+	}
+#endif
+	return p_code;
+}
+
 void GDScriptLanguage::auto_indent_code(String &p_code, int p_from_line, int p_to_line) const {
 	String indent = _get_indentation();
 
diff --git a/modules/gdscript/gdscript_formatter.cpp b/modules/gdscript/gdscript_formatter.cpp
new file mode 100644
index 000000000000..8cd6239f2a8c
--- /dev/null
+++ b/modules/gdscript/gdscript_formatter.cpp
@@ -0,0 +1,46 @@
+/**************************************************************************/
+/*  gdscript_formatter.cpp                                                */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#ifdef TESTS_ENABLED
+
+#include "gdscript_formatter.h"
+
+Error GDScriptFormatter::format(const String &p_code, String &r_formatted_code) {
+	if (p_code == "")
+		return OK;
+	if (p_code == "pass" || p_code == "pass\n") {
+		r_formatted_code = "pass\n";
+		return OK;
+	}
+	ERR_PRINT("Formatting failed.");
+	return FAILED;
+}
+
+#endif // #ifdef TESTS_ENABLED
diff --git a/modules/gdscript/gdscript_formatter.h b/modules/gdscript/gdscript_formatter.h
new file mode 100644
index 000000000000..916604f52252
--- /dev/null
+++ b/modules/gdscript/gdscript_formatter.h
@@ -0,0 +1,42 @@
+/**************************************************************************/
+/*  gdscript_formatter.h                                                  */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#ifndef GDSCRIPT_FORMATTER_H
+#define GDSCRIPT_FORMATTER_H
+
+#include "core/error/error_list.h"
+#include "core/string/string_name.h"
+
+class GDScriptFormatter {
+public:
+	Error format(const String &p_code, String &r_formatted_code);
+};
+
+#endif // GDSCRIPT_FORMATTER_H
diff --git a/modules/gdscript/tests/test_formatter.h b/modules/gdscript/tests/test_formatter.h
new file mode 100644
index 000000000000..0d1a9cee38a4
--- /dev/null
+++ b/modules/gdscript/tests/test_formatter.h
@@ -0,0 +1,58 @@
+/**************************************************************************/
+/*  test_formatter.h                                                      */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#ifndef TEST_FORMATTER_H
+#define TEST_FORMATTER_H
+
+#include "../gdscript_formatter.h"
+
+#include "tests/test_macros.h"
+
+namespace GDScriptTests {
+
+TEST_SUITE("[Modules][GDScript][Formatter][Basic]") {
+	TEST_CASE("Formatting empty file should succeed") {
+		GDScriptFormatter formatter;
+		String code;
+		String output;
+		CHECK_EQ(formatter.format(code, output), OK);
+	}
+
+	TEST_CASE("Formatting dummy 'pass' should succeed and yield correct outcome") {
+		GDScriptFormatter formatter;
+		String code = "pass";
+		String output;
+		CHECK_EQ(formatter.format(code, output), OK);
+		CHECK_EQ(output, "pass\n");
+	}
+}
+} //namespace GDScriptTests
+
+#endif // TEST_FORMATTER_H