diff --git a/src/dependency_injector/providers.c b/src/dependency_injector/providers.c
index 3503b1aa..f7cc72a8 100644
--- a/src/dependency_injector/providers.c
+++ b/src/dependency_injector/providers.c
@@ -34208,7 +34208,7 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_19ConfigurationOption
  * 
  *         config_content = _resolve_config_env_markers(             # <<<<<<<<<<<<<<
  *             config_content,
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  */
   __Pyx_GetModuleGlobalName(__pyx_t_5, __pyx_n_s_resolve_config_env_markers); if (unlikely(!__pyx_t_5)) __PYX_ERR(1, 1596, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_5);
@@ -34217,7 +34217,7 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_19ConfigurationOption
  * 
  *         config_content = _resolve_config_env_markers(
  *             config_content,             # <<<<<<<<<<<<<<
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  *         )
  */
   if (unlikely(!__pyx_v_config_content)) { __Pyx_RaiseUnboundLocalError("config_content"); __PYX_ERR(1, 1597, __pyx_L1_error) }
@@ -34227,7 +34227,7 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_19ConfigurationOption
  * 
  *         config_content = _resolve_config_env_markers(             # <<<<<<<<<<<<<<
  *             config_content,
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  */
   __pyx_t_1 = PyTuple_New(1); if (unlikely(!__pyx_t_1)) __PYX_ERR(1, 1596, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_1);
@@ -34238,20 +34238,49 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_19ConfigurationOption
   /* "dependency_injector/providers.pyx":1598
  *         config_content = _resolve_config_env_markers(
  *             config_content,
- *             envs_required=envs_required,             # <<<<<<<<<<<<<<
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),             # <<<<<<<<<<<<<<
  *         )
  *         config = yaml.load(config_content, loader)
  */
   __pyx_t_4 = __Pyx_PyDict_NewPresized(1); if (unlikely(!__pyx_t_4)) __PYX_ERR(1, 1598, __pyx_L1_error)
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+  __pyx_t_3 = __Pyx_PyObject_IsTrue(__pyx_v_envs_required); if (unlikely(__pyx_t_3 < 0)) __PYX_ERR(1, 1598, __pyx_L1_error)
+  if (!__pyx_t_3) {
+  } else {
+    __Pyx_INCREF(__pyx_v_envs_required);
+    __pyx_t_10 = __pyx_v_envs_required;
+    goto __pyx_L34_bool_binop_done;
+  }
+  __pyx_t_18 = __Pyx_PyObject_GetAttrStr(((PyObject *)__pyx_v_self), __pyx_n_s_is_strict_mode_enabled); if (unlikely(!__pyx_t_18)) __PYX_ERR(1, 1598, __pyx_L1_error)
+  __Pyx_GOTREF(__pyx_t_18);
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+  if (CYTHON_UNPACK_METHODS && likely(PyMethod_Check(__pyx_t_18))) {
+    __pyx_t_19 = PyMethod_GET_SELF(__pyx_t_18);
+    if (likely(__pyx_t_19)) {
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+      __Pyx_INCREF(__pyx_t_19);
+      __Pyx_INCREF(function);
+      __Pyx_DECREF_SET(__pyx_t_18, function);
+    }
+  }
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+  __Pyx_XDECREF(__pyx_t_19); __pyx_t_19 = 0;
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+  __Pyx_DECREF(__pyx_t_17); __pyx_t_17 = 0;
+  __pyx_L34_bool_binop_done:;
+  if (PyDict_SetItem(__pyx_t_4, __pyx_n_s_envs_required, __pyx_t_10) < 0) __PYX_ERR(1, 1598, __pyx_L1_error)
+  __Pyx_DECREF(__pyx_t_10); __pyx_t_10 = 0;
 
   /* "dependency_injector/providers.pyx":1596
  *             return
  * 
  *         config_content = _resolve_config_env_markers(             # <<<<<<<<<<<<<<
  *             config_content,
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  */
   __pyx_t_10 = __Pyx_PyObject_Call(__pyx_t_5, __pyx_t_1, __pyx_t_4); if (unlikely(!__pyx_t_10)) __PYX_ERR(1, 1596, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_10);
@@ -34262,7 +34291,7 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_19ConfigurationOption
   __pyx_t_10 = 0;
 
   /* "dependency_injector/providers.pyx":1600
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  *         )
  *         config = yaml.load(config_content, loader)             # <<<<<<<<<<<<<<
  * 
@@ -41546,7 +41575,7 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_13Configuration_46fro
  * 
  *         config_content = _resolve_config_env_markers(             # <<<<<<<<<<<<<<
  *             config_content,
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  */
   __Pyx_GetModuleGlobalName(__pyx_t_5, __pyx_n_s_resolve_config_env_markers); if (unlikely(!__pyx_t_5)) __PYX_ERR(1, 2026, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_5);
@@ -41555,7 +41584,7 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_13Configuration_46fro
  * 
  *         config_content = _resolve_config_env_markers(
  *             config_content,             # <<<<<<<<<<<<<<
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  *         )
  */
   if (unlikely(!__pyx_v_config_content)) { __Pyx_RaiseUnboundLocalError("config_content"); __PYX_ERR(1, 2027, __pyx_L1_error) }
@@ -41565,7 +41594,7 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_13Configuration_46fro
  * 
  *         config_content = _resolve_config_env_markers(             # <<<<<<<<<<<<<<
  *             config_content,
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  */
   __pyx_t_1 = PyTuple_New(1); if (unlikely(!__pyx_t_1)) __PYX_ERR(1, 2026, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_1);
@@ -41576,20 +41605,49 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_13Configuration_46fro
   /* "dependency_injector/providers.pyx":2028
  *         config_content = _resolve_config_env_markers(
  *             config_content,
- *             envs_required=envs_required,             # <<<<<<<<<<<<<<
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),             # <<<<<<<<<<<<<<
  *         )
  *         config = yaml.load(config_content, loader)
  */
   __pyx_t_4 = __Pyx_PyDict_NewPresized(1); if (unlikely(!__pyx_t_4)) __PYX_ERR(1, 2028, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_4);
-  if (PyDict_SetItem(__pyx_t_4, __pyx_n_s_envs_required, __pyx_v_envs_required) < 0) __PYX_ERR(1, 2028, __pyx_L1_error)
+  __pyx_t_3 = __Pyx_PyObject_IsTrue(__pyx_v_envs_required); if (unlikely(__pyx_t_3 < 0)) __PYX_ERR(1, 2028, __pyx_L1_error)
+  if (!__pyx_t_3) {
+  } else {
+    __Pyx_INCREF(__pyx_v_envs_required);
+    __pyx_t_10 = __pyx_v_envs_required;
+    goto __pyx_L34_bool_binop_done;
+  }
+  __pyx_t_18 = __Pyx_PyObject_GetAttrStr(((PyObject *)__pyx_v_self), __pyx_n_s_is_strict_mode_enabled); if (unlikely(!__pyx_t_18)) __PYX_ERR(1, 2028, __pyx_L1_error)
+  __Pyx_GOTREF(__pyx_t_18);
+  __pyx_t_19 = NULL;
+  if (CYTHON_UNPACK_METHODS && likely(PyMethod_Check(__pyx_t_18))) {
+    __pyx_t_19 = PyMethod_GET_SELF(__pyx_t_18);
+    if (likely(__pyx_t_19)) {
+      PyObject* function = PyMethod_GET_FUNCTION(__pyx_t_18);
+      __Pyx_INCREF(__pyx_t_19);
+      __Pyx_INCREF(function);
+      __Pyx_DECREF_SET(__pyx_t_18, function);
+    }
+  }
+  __pyx_t_17 = (__pyx_t_19) ? __Pyx_PyObject_CallOneArg(__pyx_t_18, __pyx_t_19) : __Pyx_PyObject_CallNoArg(__pyx_t_18);
+  __Pyx_XDECREF(__pyx_t_19); __pyx_t_19 = 0;
+  if (unlikely(!__pyx_t_17)) __PYX_ERR(1, 2028, __pyx_L1_error)
+  __Pyx_GOTREF(__pyx_t_17);
+  __Pyx_DECREF(__pyx_t_18); __pyx_t_18 = 0;
+  __Pyx_INCREF(__pyx_t_17);
+  __pyx_t_10 = __pyx_t_17;
+  __Pyx_DECREF(__pyx_t_17); __pyx_t_17 = 0;
+  __pyx_L34_bool_binop_done:;
+  if (PyDict_SetItem(__pyx_t_4, __pyx_n_s_envs_required, __pyx_t_10) < 0) __PYX_ERR(1, 2028, __pyx_L1_error)
+  __Pyx_DECREF(__pyx_t_10); __pyx_t_10 = 0;
 
   /* "dependency_injector/providers.pyx":2026
  *             return
  * 
  *         config_content = _resolve_config_env_markers(             # <<<<<<<<<<<<<<
  *             config_content,
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  */
   __pyx_t_10 = __Pyx_PyObject_Call(__pyx_t_5, __pyx_t_1, __pyx_t_4); if (unlikely(!__pyx_t_10)) __PYX_ERR(1, 2026, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_10);
@@ -41600,7 +41658,7 @@ static PyObject *__pyx_pf_19dependency_injector_9providers_13Configuration_46fro
   __pyx_t_10 = 0;
 
   /* "dependency_injector/providers.pyx":2030
- *             envs_required=envs_required,
+ *             envs_required=envs_required or self._is_strict_mode_enabled(),
  *         )
  *         config = yaml.load(config_content, loader)             # <<<<<<<<<<<<<<
  * 
diff --git a/src/dependency_injector/providers.pyx b/src/dependency_injector/providers.pyx
index 3a5d0db6..548412d4 100644
--- a/src/dependency_injector/providers.pyx
+++ b/src/dependency_injector/providers.pyx
@@ -1595,7 +1595,7 @@ cdef class ConfigurationOption(Provider):
 
         config_content = _resolve_config_env_markers(
             config_content,
-            envs_required=envs_required,
+            envs_required=envs_required or self._is_strict_mode_enabled(),
         )
         config = yaml.load(config_content, loader)
 
@@ -2025,7 +2025,7 @@ cdef class Configuration(Object):
 
         config_content = _resolve_config_env_markers(
             config_content,
-            envs_required=envs_required,
+            envs_required=envs_required or self._is_strict_mode_enabled(),
         )
         config = yaml.load(config_content, loader)
 
diff --git a/tests/unit/providers/test_configuration_py2_py3.py b/tests/unit/providers/test_configuration_py2_py3.py
index 978a686e..f30cb2ad 100644
--- a/tests/unit/providers/test_configuration_py2_py3.py
+++ b/tests/unit/providers/test_configuration_py2_py3.py
@@ -905,7 +905,7 @@ class ConfigFromYamlWithEnvInterpolationTests(unittest.TestCase):
         self.assertEqual(self.config.section1.value2(), 'test-path/path')
 
     @unittest.skipIf(sys.version_info[:2] == (3, 4), 'PyYAML does not support Python 3.4')
-    def test_missing_envs(self):
+    def test_missing_envs_not_required(self):
         del os.environ['CONFIG_TEST_ENV']
         del os.environ['CONFIG_TEST_PATH']
 
@@ -930,6 +930,39 @@ class ConfigFromYamlWithEnvInterpolationTests(unittest.TestCase):
         self.assertIsNone(self.config.section1.value1())
         self.assertEqual(self.config.section1.value2(), '/path')
 
+    @unittest.skipIf(sys.version_info[:2] == (3, 4), 'PyYAML does not support Python 3.4')
+    def test_missing_envs_required(self):
+        with open(self.config_file, 'w') as config_file:
+            config_file.write(
+                'section:\n'
+                '  undefined: ${UNDEFINED}\n'
+            )
+
+        with self.assertRaises(ValueError) as context:
+            self.config.from_yaml(self.config_file, envs_required=True)
+
+        self.assertEqual(
+            str(context.exception),
+            'Missing required environment variable "UNDEFINED"',
+        )
+
+    @unittest.skipIf(sys.version_info[:2] == (3, 4), 'PyYAML does not support Python 3.4')
+    def test_missing_envs_strict_mode(self):
+        with open(self.config_file, 'w') as config_file:
+            config_file.write(
+                'section:\n'
+                '  undefined: ${UNDEFINED}\n'
+            )
+
+        self.config.set_strict(True)
+        with self.assertRaises(ValueError) as context:
+            self.config.from_yaml(self.config_file)
+
+        self.assertEqual(
+            str(context.exception),
+            'Missing required environment variable "UNDEFINED"',
+        )
+
     @unittest.skipIf(sys.version_info[:2] == (3, 4), 'PyYAML does not support Python 3.4')
     def test_option_missing_envs(self):
         del os.environ['CONFIG_TEST_ENV']
@@ -956,6 +989,39 @@ class ConfigFromYamlWithEnvInterpolationTests(unittest.TestCase):
         self.assertIsNone(self.config.option.section1.value1())
         self.assertEqual(self.config.option.section1.value2(), '/path')
 
+    @unittest.skipIf(sys.version_info[:2] == (3, 4), 'PyYAML does not support Python 3.4')
+    def test_option_missing_envs_required(self):
+        with open(self.config_file, 'w') as config_file:
+            config_file.write(
+                'section:\n'
+                '  undefined: ${UNDEFINED}\n'
+            )
+
+        with self.assertRaises(ValueError) as context:
+            self.config.option.from_yaml(self.config_file, envs_required=True)
+
+        self.assertEqual(
+            str(context.exception),
+            'Missing required environment variable "UNDEFINED"',
+        )
+
+    @unittest.skipIf(sys.version_info[:2] == (3, 4), 'PyYAML does not support Python 3.4')
+    def test_option_missing_envs_strict_mode(self):
+        with open(self.config_file, 'w') as config_file:
+            config_file.write(
+                'section:\n'
+                '  undefined: ${UNDEFINED}\n'
+            )
+
+        self.config.set_strict(True)
+        with self.assertRaises(ValueError) as context:
+            self.config.option.from_yaml(self.config_file)
+
+        self.assertEqual(
+            str(context.exception),
+            'Missing required environment variable "UNDEFINED"',
+        )
+
     @unittest.skipIf(sys.version_info[:2] == (3, 4), 'PyYAML does not support Python 3.4')
     def test_default_values(self):
         os.environ['DEFINED'] = 'defined'