diff --git a/src/main/java/org/json/JSONTokener.java b/src/main/java/org/json/JSONTokener.java
index ffe12d6..05a6e34 100644
--- a/src/main/java/org/json/JSONTokener.java
+++ b/src/main/java/org/json/JSONTokener.java
@@ -513,18 +513,19 @@ public class JSONTokener {
         Object obj = JSONObject.stringToValue(string);
         // if obj is a boolean, look at string
         if (jsonParserConfiguration != null &&
-                jsonParserConfiguration.isStrictMode() && obj instanceof Boolean) {
-            if (!"true".equals(string) && !"false".equals(string)) {
+                jsonParserConfiguration.isStrictMode()) {
+            if (obj instanceof Boolean && !"true".equals(string) && !"false".equals(string)) {
+                // Strict mode only allows lowercase true or false
                 throw this.syntaxError(String.format("Strict mode error: Value '%s' is not lowercase boolean", obj));
             }
-        }
-
-
-        // Strict mode only allows strings with explicit double quotes
-        if (jsonParserConfiguration != null &&
-                jsonParserConfiguration.isStrictMode() &&
-                obj instanceof String) {
-            throw this.syntaxError(String.format("Strict mode error: Value '%s' is not surrounded by quotes", obj));
+            else if (obj == JSONObject.NULL && !"null".equals(string)) {
+                // Strint mode only allows lowercase null
+                throw this.syntaxError(String.format("Strict mode error: Value '%s' is not lowercase null", obj));
+            }
+            else if (obj instanceof String) {
+                // Strict mode only allows strings with explicit double quotes
+                throw this.syntaxError(String.format("Strict mode error: Value '%s' is not surrounded by quotes", obj));
+            }
         }
         return obj;
     }
diff --git a/src/test/java/org/json/junit/JSONObjectTest.java b/src/test/java/org/json/junit/JSONObjectTest.java
index 50319a8..52a5240 100644
--- a/src/test/java/org/json/junit/JSONObjectTest.java
+++ b/src/test/java/org/json/junit/JSONObjectTest.java
@@ -3998,7 +3998,7 @@ public class JSONObjectTest {
     }
 
     @Test
-    public void test_strictModeWithMisCasedBooleanValue(){
+    public void test_strictModeWithMisCasedBooleanOrNullValue(){
         JSONParserConfiguration jsonParserConfiguration = new JSONParserConfiguration().withStrictMode();
 
         try{
@@ -4009,6 +4009,10 @@ public class JSONObjectTest {
             JSONObject j2 = new JSONObject("{\"a\":TRUE}", jsonParserConfiguration);
             fail("Expected an exception");
         } catch (JSONException e) { }
+        try{
+            JSONObject j2 = new JSONObject("{\"a\":nUlL}", jsonParserConfiguration);
+            fail("Expected an exception");
+        } catch (JSONException e) { }
     }
 
     @Test