diff --git a/MODULE.bazel b/MODULE.bazel
index 5cc38dd..00a5354 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -7,5 +7,5 @@ module(
 bazel_dep(name = "rules_cc", version = "0.0.8")
 bazel_dep(name = "bazel_skylib", version = "1.4.2")
 bazel_dep(name = "magic_enum", version = "0.9.3")
-bazel_dep(name = "ecsact_runtime", version = "0.5.2")
+bazel_dep(name = "ecsact_runtime", version = "0.5.3")
 bazel_dep(name = "ecsact_parse", version = "0.3.3")
diff --git a/ecsact/interpret/eval.cc b/ecsact/interpret/eval.cc
index 50f4608..16b0588 100644
--- a/ecsact/interpret/eval.cc
+++ b/ecsact/interpret/eval.cc
@@ -15,6 +15,7 @@
 #include "ecsact/parse.h"
 #include "ecsact/runtime/dynamic.h"
 #include "ecsact/runtime/meta.hh"
+#include "ecsact/runtime/meta.h"
 
 #include "./detail/file_eval_error.hh"
 
@@ -1402,6 +1403,13 @@ static auto eval_system_notify_component_statement(
 	std::span<const ecsact_statement>& context_stack,
 	const ecsact_statement&            statement
 ) -> ecsact_eval_error {
+	if(context_stack.size() < 2) {
+		return ecsact_eval_error{
+			.code = ECSACT_EVAL_ERR_INVALID_CONTEXT,
+			.relevant_content = {},
+		};
+	}
+	
 	auto [context, err] =
 		expect_context(context_stack, {ECSACT_STATEMENT_SYSTEM_NOTIFY});
 
@@ -1430,7 +1438,7 @@ static auto eval_system_notify_component_statement(
 
 	auto sys_like_id = find_by_statement<ecsact_system_like_id>( //
 		package_id,
-		*context
+		context_stack[context_stack.size() - 2]
 	);
 
 	auto comp_like_name = std::string( //
@@ -1464,6 +1472,16 @@ static auto eval_system_notify_component_statement(
 		};
 	}
 
+	for(auto&& [existing_comp_id, _] :
+			ecsact::meta::system_notify_settings(*sys_like_id)) {
+		if(existing_comp_id == *comp_like_id) {
+			return ecsact_eval_error{
+				.code = ECSACT_EVAL_ERR_DUPLICATE_NOTIFY_COMPONENT,
+				.relevant_content = {},
+			};
+		}
+	}
+
 	ecsact_set_system_notify_component_setting(
 		*sys_like_id,
 		*comp_like_id,
diff --git a/ecsact/interpret/eval_error.h b/ecsact/interpret/eval_error.h
index ba924f8..7e14ff5 100644
--- a/ecsact/interpret/eval_error.h
+++ b/ecsact/interpret/eval_error.h
@@ -72,6 +72,9 @@ typedef enum ecsact_eval_error_code {
 	/// The notify statement must be after all capability statements.
 	ECSACT_EVAL_ERR_NOTIFY_BEFORE_SYSTEM_COMPONENT,
 
+	// More than one system notify component statement for the same component.
+	ECSACT_EVAL_ERR_DUPLICATE_NOTIFY_COMPONENT,
+
 	/// Internal error. Should not happen and is an indiciation of a bug.
 	ECSACT_EVAL_ERR_INTERNAL = 999,
 
diff --git a/test/MODULE.bazel b/test/MODULE.bazel
index 160db3e..7b067b2 100644
--- a/test/MODULE.bazel
+++ b/test/MODULE.bazel
@@ -4,7 +4,7 @@ bazel_dep(name = "rules_cc", version = "0.0.8")
 bazel_dep(name = "bazel_skylib", version = "1.4.2")
 bazel_dep(name = "googletest", version = "1.14.0")
 bazel_dep(name = "ecsact_parse", version = "0.3.3")
-bazel_dep(name = "ecsact_runtime", version = "0.5.2")
+bazel_dep(name = "ecsact_runtime", version = "0.5.3")
 
 bazel_dep(name = "bazel_sundry")
 bazel_dep(name = "ecsact_interpret")
diff --git a/test/errors/BUILD.bazel b/test/errors/BUILD.bazel
index 5debf3a..52c1f59 100644
--- a/test/errors/BUILD.bazel
+++ b/test/errors/BUILD.bazel
@@ -3,6 +3,7 @@ load("@ecsact_interpret//bazel:copts.bzl", "copts")
 
 # buildifier: keep sorted
 _TESTS = [
+    "duplicate_notice_components",
     "invalid_notify_settings",
     "no_capabilities",
     "no_package_statement_first",
diff --git a/test/errors/duplicate_notice_components.cc b/test/errors/duplicate_notice_components.cc
new file mode 100644
index 0000000..f0af270
--- /dev/null
+++ b/test/errors/duplicate_notice_components.cc
@@ -0,0 +1,10 @@
+#include "gtest/gtest.h"
+#include "ecsact/interpret/eval.h"
+
+#include "test_lib.hh"
+
+TEST(DuplicateNoticeComponents, DuplicateNoticeComponents) {
+	auto errs = ecsact_interpret_test_files({"errors/duplicate_notice_components.ecsact"});
+	ASSERT_EQ(errs.size(), 1);
+	ASSERT_EQ(errs[0].eval_error, ECSACT_EVAL_ERR_DUPLICATE_NOTIFY_COMPONENT);
+}
diff --git a/test/errors/duplicate_notice_components.ecsact b/test/errors/duplicate_notice_components.ecsact
new file mode 100644
index 0000000..5a56619
--- /dev/null
+++ b/test/errors/duplicate_notice_components.ecsact
@@ -0,0 +1,14 @@
+package error.duplicate_notice_components;
+
+component ExampleComponent {
+  i32 num;
+}
+
+system DuplicateNoticeComponents {
+  readwrite ExampleComponent;
+
+  notify {
+    always ExampleComponent;
+    oninit ExampleComponent;
+  }
+}