diff --git a/config.xsd b/config.xsd
index 9f8676ce823..c119abdda45 100644
--- a/config.xsd
+++ b/config.xsd
@@ -95,6 +95,7 @@
         <xs:attribute name="usePhpDocPropertiesWithoutMagicCall" type="xs:boolean" default="false" />
         <xs:attribute name="skipChecksOnUnresolvableIncludes" type="xs:boolean" default="false" />
         <xs:attribute name="sealAllMethods" type="xs:boolean" default="false" />
+        <xs:attribute name="sealAllProperties" type="xs:boolean" default="false" />
         <xs:attribute name="runTaintAnalysis" type="xs:boolean" default="false" />
         <xs:attribute name="usePhpStormMetaPath" type="xs:boolean" default="true" />
         <xs:attribute name="allowInternalNamedArgumentCalls" type="xs:boolean" default="true" />
diff --git a/docs/running_psalm/configuration.md b/docs/running_psalm/configuration.md
index 6a84f20742e..21a253e0be0 100644
--- a/docs/running_psalm/configuration.md
+++ b/docs/running_psalm/configuration.md
@@ -305,6 +305,16 @@ This defaults to `false`.
 
 When `true`, Psalm will treat all classes as if they had sealed methods, meaning that if you implement the magic method `__call`, you also have to add `@method` for each magic method. Defaults to false.
 
+#### sealAllProperties
+
+```xml
+<psalm
+  sealAllProperties="[bool]"
+>
+```
+
+When `true`, Psalm will treat all classes as if they had sealed properties, meaning that Psalm will disallow getting and setting any properties not contained in a list of `@property` (or `@property-read`/`@property-write`) annotations and not explicitly defined as a `property`. Defaults to false.
+
 #### runTaintAnalysis
 
 ```xml
diff --git a/src/Psalm/Config.php b/src/Psalm/Config.php
index db8f8f06df1..a8310c21120 100644
--- a/src/Psalm/Config.php
+++ b/src/Psalm/Config.php
@@ -346,6 +346,11 @@ class Config
      */
     public $seal_all_methods = false;
 
+    /**
+     * @var bool
+     */
+    public $seal_all_properties = false;
+
     /**
      * @var bool
      */
@@ -907,6 +912,7 @@ private static function fromXmlAndPaths(
             'reportMixedIssues' => 'show_mixed_issues',
             'skipChecksOnUnresolvableIncludes' => 'skip_checks_on_unresolvable_includes',
             'sealAllMethods' => 'seal_all_methods',
+            'sealAllProperties' => 'seal_all_properties',
             'runTaintAnalysis' => 'run_taint_analysis',
             'usePhpStormMetaPath' => 'use_phpstorm_meta_path',
             'allowInternalNamedArgumentsCalls' => 'allow_internal_named_arg_calls',
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/ExistingAtomicMethodCallAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/ExistingAtomicMethodCallAnalyzer.php
index 1fda720d0c2..26faf4e593e 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/ExistingAtomicMethodCallAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/ExistingAtomicMethodCallAnalyzer.php
@@ -548,7 +548,7 @@ private static function getMagicGetterOrSetterProperty(
             case '__set':
                 // If `@psalm-seal-properties` is set, the property must be defined with
                 // a `@property` annotation
-                if ($class_storage->sealed_properties
+                if (($class_storage->sealed_properties || $codebase->config->seal_all_properties)
                     && !isset($class_storage->pseudo_property_set_types['$' . $prop_name])
                     && IssueBuffer::accepts(
                         new UndefinedThisPropertyAssignment(
@@ -647,7 +647,7 @@ private static function getMagicGetterOrSetterProperty(
             case '__get':
                 // If `@psalm-seal-properties` is set, the property must be defined with
                 // a `@property` annotation
-                if ($class_storage->sealed_properties
+                if (($class_storage->sealed_properties || $codebase->config->seal_all_properties)
                     && !isset($class_storage->pseudo_property_get_types['$' . $prop_name])
                     && IssueBuffer::accepts(
                         new UndefinedThisPropertyFetch(
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php
index ee9f642c186..b0961eec718 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/AtomicPropertyFetchAnalyzer.php
@@ -676,7 +676,9 @@ private static function propertyFetchCanBeAnalyzed(
              * If we have an explicit list of all allowed magic properties on the class, and we're
              * not in that list, fall through
              */
-            if (!$class_storage->sealed_properties && !$override_property_visibility) {
+            if (!($class_storage->sealed_properties || $codebase->config->seal_all_properties)
+                && !$override_property_visibility
+            ) {
                 return false;
             }
 
diff --git a/tests/MagicPropertyTest.php b/tests/MagicPropertyTest.php
index 62d0dd9773b..f142bb1bd65 100644
--- a/tests/MagicPropertyTest.php
+++ b/tests/MagicPropertyTest.php
@@ -4,6 +4,7 @@
 
 use Psalm\Config;
 use Psalm\Context;
+use Psalm\Exception\CodeException;
 use Psalm\Tests\Traits\InvalidCodeAnalysisTestTrait;
 use Psalm\Tests\Traits\ValidCodeAnalysisTestTrait;
 
@@ -1159,4 +1160,28 @@ class A {
             ],
         ];
     }
+
+    public function testSealAllMethodsWithoutFoo(): void
+    {
+        Config::getInstance()->seal_all_properties = true;
+
+        $this->addFile(
+            'somefile.php',
+            '<?php
+              class A {
+                public function __get(string $name) {}
+              }
+
+              class B extends A {}
+
+              $b = new B();
+              $result = $b->foo;
+              '
+        );
+
+        $error_message = 'UndefinedMagicPropertyFetch';
+        $this->expectException(CodeException::class);
+        $this->expectExceptionMessage($error_message);
+        $this->analyzeFile('somefile.php', new Context());
+    }
 }