diff --git a/lint/rules.go b/lint/rules.go
index 49d934b..b04ef4d 100644
--- a/lint/rules.go
+++ b/lint/rules.go
@@ -19,6 +19,30 @@ func TestAll(rulesPath string) error {
 		return err
 	}
 
+	// Check for duplicate rule numbers
+	ruleNumberMap := make(map[string][]string)
+	for _, rule := range allRules {
+		if rule.RuleNumber != "" {
+			ruleNumberMap[rule.RuleNumber] = append(ruleNumberMap[rule.RuleNumber], rule.Path)
+		}
+	}
+
+	// Report duplicates
+	hasDuplicates := false
+	for ruleNumber, paths := range ruleNumberMap {
+		if len(paths) > 1 {
+			hasDuplicates = true
+			log.Errorf("Duplicate rule number '%s' found in the following rules:", ruleNumber)
+			for _, path := range paths {
+				log.Errorf("  - %s", path)
+			}
+		}
+	}
+
+	if hasDuplicates {
+		return fmt.Errorf("found duplicate rule numbers")
+	}
+
 	for _, rule := range allRules {
 		runTestCases(rule)
 	}
diff --git a/lint/rules_test.go b/lint/rules_test.go
index 08493ba..5010082 100644
--- a/lint/rules_test.go
+++ b/lint/rules_test.go
@@ -1,6 +1,8 @@
 package lint
 
 import (
+	"os"
+	"path/filepath"
 	"testing"
 )
 
@@ -13,3 +15,160 @@ func TestAllRules(t *testing.T) {
 		}
 	})
 }
+
+func TestDuplicateRuleNumbers(t *testing.T) {
+	// Create a temporary directory for test rules
+	tempDir := t.TempDir()
+
+	// Create two rules with the same rule number
+	rule1Content := `# METADATA
+# scope: package
+# title: Test Rule 1
+# description: First test rule
+# custom:
+#  category: Test
+#  rulename: TestRule1
+#  severity: LOW
+#  rulenumber: 001_0001
+#  remediation: Fix it
+#  input: .*test\.yaml
+package app.test.rule1
+import rego.v1
+
+default allow := false
+allow if count(errors) == 0
+errors contains "test error" if false
+`
+
+	rule2Content := `# METADATA
+# scope: package
+# title: Test Rule 2
+# description: Second test rule with same number
+# custom:
+#  category: Test
+#  rulename: TestRule2
+#  severity: LOW
+#  rulenumber: 001_0001
+#  remediation: Fix it
+#  input: .*test\.yaml
+package app.test.rule2
+import rego.v1
+
+default allow := false
+allow if count(errors) == 0
+errors contains "test error" if false
+`
+
+	// Write the rule files
+	rule1Path := filepath.Join(tempDir, "rule1.rego")
+	rule2Path := filepath.Join(tempDir, "rule2.rego")
+
+	err := os.WriteFile(rule1Path, []byte(rule1Content), 0644)
+	if err != nil {
+		t.Fatalf("Failed to write rule1: %v", err)
+	}
+
+	err = os.WriteFile(rule2Path, []byte(rule2Content), 0644)
+	if err != nil {
+		t.Fatalf("Failed to write rule2: %v", err)
+	}
+
+	// Test that duplicate rule numbers are detected
+	err = TestAll(tempDir)
+	if err == nil {
+		t.Error("Expected error for duplicate rule numbers, but got nil")
+	}
+
+	if err != nil && err.Error() != "found duplicate rule numbers" {
+		t.Errorf("Expected 'found duplicate rule numbers' error, got: %v", err)
+	}
+}
+
+func TestUniqueRuleNumbers(t *testing.T) {
+	// Create a temporary directory for test rules
+	tempDir := t.TempDir()
+
+	// Create two rules with different rule numbers
+	rule1Content := `# METADATA
+# scope: package
+# title: Test Rule 1
+# description: First test rule
+# custom:
+#  category: Test
+#  rulename: TestRule1
+#  severity: LOW
+#  rulenumber: 001_0001
+#  remediation: Fix it
+#  input: .*test\.yaml
+package app.test.rule1
+import rego.v1
+
+default allow := false
+allow if count(errors) == 0
+errors contains "test error" if false
+`
+
+	rule2Content := `# METADATA
+# scope: package
+# title: Test Rule 2
+# description: Second test rule with different number
+# custom:
+#  category: Test
+#  rulename: TestRule2
+#  severity: LOW
+#  rulenumber: 001_0002
+#  remediation: Fix it
+#  input: .*test\.yaml
+package app.test.rule2
+import rego.v1
+
+default allow := false
+allow if count(errors) == 0
+errors contains "test error" if false
+`
+
+	// Write the rule files
+	rule1Path := filepath.Join(tempDir, "rule1.rego")
+	rule2Path := filepath.Join(tempDir, "rule2.rego")
+
+	// Create test files for the rules
+	testFile1 := filepath.Join(tempDir, "rule1_test.yaml")
+	testFile2 := filepath.Join(tempDir, "rule2_test.yaml")
+
+	testContent := `TestCases:
+  - name: "test case"
+    input:
+      test: true
+    allow: true
+`
+
+	err := os.WriteFile(rule1Path, []byte(rule1Content), 0644)
+	if err != nil {
+		t.Fatalf("Failed to write rule1: %v", err)
+	}
+
+	err = os.WriteFile(rule2Path, []byte(rule2Content), 0644)
+	if err != nil {
+		t.Fatalf("Failed to write rule2: %v", err)
+	}
+
+	err = os.WriteFile(testFile1, []byte(testContent), 0644)
+	if err != nil {
+		t.Fatalf("Failed to write test file 1: %v", err)
+	}
+
+	err = os.WriteFile(testFile2, []byte(testContent), 0644)
+	if err != nil {
+		t.Fatalf("Failed to write test file 2: %v", err)
+	}
+
+	// Test that unique rule numbers pass validation
+	err = TestAll(tempDir)
+	if err != nil {
+		// We expect errors from running the actual tests, but not from duplicate rule numbers
+		if err.Error() == "found duplicate rule numbers" {
+			t.Errorf("Should not get duplicate rule numbers error with unique numbers: %v", err)
+		}
+		// Other errors from test execution are fine for this test
+	}
+}