diff --git a/includes/Checker/Checks/Plugin_Repo/File_Type_Check.php b/includes/Checker/Checks/Plugin_Repo/File_Type_Check.php
index dfdc435d0..f1e547347 100644
--- a/includes/Checker/Checks/Plugin_Repo/File_Type_Check.php
+++ b/includes/Checker/Checks/Plugin_Repo/File_Type_Check.php
@@ -29,7 +29,8 @@ class File_Type_Check extends Abstract_File_Check {
 	const TYPE_VCS         = 4;
 	const TYPE_HIDDEN      = 8;
 	const TYPE_APPLICATION = 16;
-	const TYPE_ALL         = 31; // Same as all of the above with bitwise OR.
+	const TYPE_BADLY_NAMED = 32;
+	const TYPE_ALL         = 63; // Same as all of the above with bitwise OR.
 
 	/**
 	 * Bitwise flags to control check behavior.
@@ -90,6 +91,10 @@ protected function check_files( Check_Result $result, array $files ) {
 		if ( $this->flags & self::TYPE_APPLICATION ) {
 			$this->look_for_application_files( $result, $files );
 		}
+		if ( $this->flags & self::TYPE_BADLY_NAMED ) {
+			// Check for badly named files.
+			$this->look_for_badly_named_files( $result, $files );
+		}
 	}
 
 	/**
@@ -244,6 +249,42 @@ protected function look_for_application_files( Check_Result $result, array $file
 		}
 	}
 
+	/**
+	 * Looks for application files and amends the given result with an error if found.
+	 *
+	 * @since 1.2.0
+	 *
+	 * @param Check_Result $result The check result to amend, including the plugin context to check.
+	 * @param array        $files  List of absolute file paths.
+	 */
+	protected function look_for_badly_named_files( Check_Result $result, array $files ) {
+		$conflict_chars = '!@#$%^&*()+=[]{};:"\'<>,?/\\|`~';
+
+		foreach ( $files as $file ) {
+			$badly_name = false;
+			if ( preg_match( '/\s/', $file ) ) {
+				$badly_name = true;
+			}
+
+			if ( preg_match( '/[' . preg_quote( $conflict_chars, '/' ) . ']/', basename( $file ) ) ) {
+				$badly_name = true;
+			}
+
+			if ( $badly_name ) {
+				$this->add_result_error_for_file(
+					$result,
+					__( 'Badly named files are not permitted.', 'plugin-check' ),
+					'badly_named_files',
+					$file,
+					0,
+					0,
+					'',
+					8
+				);
+			}
+		}
+	}
+
 	/**
 	 * Gets the description for the check.
 	 *
@@ -254,7 +295,7 @@ protected function look_for_application_files( Check_Result $result, array $file
 	 * @return string Description.
 	 */
 	public function get_description(): string {
-		return __( 'Detects the usage of hidden and compressed files, VCS directories, and application files.', 'plugin-check' );
+		return __( 'Detects the usage of hidden and compressed files, VCS directories, application files and badly named files.', 'plugin-check' );
 	}
 
 	/**
diff --git a/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/badly directory/file.php b/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/badly directory/file.php
new file mode 100644
index 000000000..5ebd0556e
--- /dev/null
+++ b/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/badly directory/file.php	
@@ -0,0 +1,2 @@
+<?php
+// File in a directory with a badly named file.
\ No newline at end of file
diff --git "a/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/badly|file%name!@#$%^&*()+=[]{};:\"'<>,?|`~.php" "b/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/badly|file%name!@#$%^&*()+=[]{};:\"'<>,?|`~.php"
new file mode 100644
index 000000000..92bee4abf
--- /dev/null
+++ "b/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/badly|file%name!@#$%^&*()+=[]{};:\"'<>,?|`~.php"
@@ -0,0 +1,3 @@
+<?php
+
+// This file has a badly named file.
\ No newline at end of file
diff --git a/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/load.php b/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/load.php
new file mode 100644
index 000000000..3979dfdc7
--- /dev/null
+++ b/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/load.php
@@ -0,0 +1,17 @@
+<?php
+/**
+ * Plugin Name: Test Plugin File Type Badly Named Files Errors
+ * Plugin URI: https://github.com/wordpress/plugin-check
+ * Description: Some plugin description.
+ * Author: WordPress Review Team
+ * Author URI: https://make.wordpress.org/performance/
+ * License: GPLv2 or later
+ * License URI: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * Text Domain: test-plugin-file-type-badly-named-files-errors
+ *
+ * @package test-plugin-file-type-badly-named-files-errors
+ */
+
+/**
+ * Plugin folder contains a file with a badly named file.
+ */
diff --git a/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/plugin name.php b/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/plugin name.php
new file mode 100644
index 000000000..2f1edaccf
--- /dev/null
+++ b/tests/phpunit/testdata/plugins/test-plugin-file-type-badly-named-files-errors/plugin name.php	
@@ -0,0 +1,3 @@
+<?php
+
+// This is an error file.
\ No newline at end of file
diff --git a/tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php b/tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php
index 8b2467321..7e73cfd36 100644
--- a/tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php
+++ b/tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php
@@ -98,4 +98,33 @@ public function test_run_without_any_file_type_errors() {
 		$this->assertEmpty( $errors );
 		$this->assertSame( 0, $check_result->get_error_count() );
 	}
+
+	public function test_run_with_badly_named_errors() {
+		// Test plugin without any forbidden file types.
+		$check_context = new Check_Context( UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-badly-named-files-errors/load.php' );
+		$check_result  = new Check_Result( $check_context );
+
+		$check = new File_Type_Check( File_Type_Check::TYPE_BADLY_NAMED );
+		$check->run( $check_result );
+
+		$errors = $check_result->get_errors();
+
+		$this->assertNotEmpty( $errors );
+		$this->assertEquals( 3, $check_result->get_error_count() );
+
+		// Check for invalid name error.
+		$this->assertArrayHasKey( 0, $errors['plugin name.php'] );
+		$this->assertArrayHasKey( 0, $errors['plugin name.php'][0] );
+		$this->assertCount( 1, wp_list_filter( $errors['plugin name.php'][0][0], array( 'code' => 'badly_named_files' ) ) );
+
+		// Badly named directory check.
+		$this->assertArrayHasKey( 0, $errors['badly directory/file.php'] );
+		$this->assertArrayHasKey( 0, $errors['badly directory/file.php'][0] );
+		$this->assertCount( 1, wp_list_filter( $errors['badly directory/file.php'][0][0], array( 'code' => 'badly_named_files' ) ) );
+
+		// Badly named file with special chars.
+		$this->assertArrayHasKey( 0, $errors['badly|file%name!@#$%^&*()+=[]{};:"\'<>,?|`~.php'] );
+		$this->assertArrayHasKey( 0, $errors['badly|file%name!@#$%^&*()+=[]{};:"\'<>,?|`~.php'][0] );
+		$this->assertCount( 1, wp_list_filter( $errors['badly|file%name!@#$%^&*()+=[]{};:"\'<>,?|`~.php'][0][0], array( 'code' => 'badly_named_files' ) ) );
+	}
 }