diff --git a/src/json-validator.cpp b/src/json-validator.cpp
index b279f23..f78ce4d 100644
--- a/src/json-validator.cpp
+++ b/src/json-validator.cpp
@@ -503,6 +503,7 @@ class type_schema : public schema
 	std::vector<std::shared_ptr<schema>> type_;
 	std::pair<bool, json> enum_, const_;
 	std::vector<std::shared_ptr<schema>> logic_;
+	bool read_only_ = false;
 
 	static std::shared_ptr<schema> make(json &schema,
 	                                    json::value_t type,
@@ -553,8 +554,15 @@ class type_schema : public schema
 					else_->validate(ptr, instance, patch, e);
 			}
 		}
-		if (instance.is_null()) {
+		
+		if (instance.is_null())
 			patch.add(nlohmann::json::json_pointer{}, default_value_);
+
+    	// enforce default value if any read only values
+		if(read_only_) {
+			auto rod_value = default_value(ptr, instance, e);
+			if(rod_value != nullptr && instance != rod_value)
+				e.error(ptr, instance, "key is read-only");
 		}
 	}
 
@@ -623,6 +631,12 @@ public:
 			sch.erase(attr);
 		}
 
+		attr = sch.find("readOnly");
+		if (attr != sch.end()) {
+			read_only_ = attr.value().get<bool>();
+			sch.erase(attr);
+		}
+
 		for (auto &key : known_keywords)
 			sch.erase(key);
 
@@ -1460,3 +1474,4 @@ json json_validator::validate(const json &instance, error_handler &err, const js
 
 } // namespace json_schema
 } // namespace nlohmann
+
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 9fa9c5b..e089d7f 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -77,3 +77,7 @@ add_test(NAME issue-189-default-values COMMAND issue-189-default-values)
 add_executable(issue-243-root-default-values issue-243-root-default-values.cpp)
 target_link_libraries(issue-243-root-default-values nlohmann_json_schema_validator)
 add_test(NAME issue-243-root-default-values COMMAND issue-243-root-default-values)
+
+add_executable(issue-212-read-only-values read-only-values.cpp)
+target_link_libraries(issue-212-read-only-values nlohmann_json_schema_validator)
+add_test(NAME issue-212-read-only-values COMMAND issue-212-read-only-values)
diff --git a/test/read-only-values.cpp b/test/read-only-values.cpp
new file mode 100644
index 0000000..4f3c28c
--- /dev/null
+++ b/test/read-only-values.cpp
@@ -0,0 +1,28 @@
+#include <nlohmann/json-schema.hpp>
+
+using nlohmann::json;
+using nlohmann::json_schema::json_validator;
+
+static const json read_only_schema = R"({
+	"type": "object",
+	"properties": {
+		"debug": {
+			"type": "boolean", 
+			"default": false,
+			"readOnly": true
+		}
+	}
+})"_json;
+
+int main() {
+	json_validator validator(read_only_schema);
+	try {
+		validator.validate(R"({
+			"debug": true
+		})"_json);
+	} catch (const std::exception&e ) {
+		return EXIT_SUCCESS;
+	}
+	
+	return EXIT_FAILURE;
+}