diff --git a/internal/chart/v3/lint/rules/template.go b/internal/chart/v3/lint/rules/template.go
index d4c62839f..204966364 100644
--- a/internal/chart/v3/lint/rules/template.go
+++ b/internal/chart/v3/lint/rules/template.go
@@ -126,7 +126,7 @@ func TemplatesWithSkipSchemaValidation(linter *support.Linter, values map[string
 		linter.RunLinterRule(support.ErrorSev, fpath, validateAllowedExtension(fileName))
 
 		// We only apply the following lint rules to yaml files
-		if filepath.Ext(fileName) != ".yaml" || filepath.Ext(fileName) == ".yml" {
+		if !isYamlFileExtension(fileName) {
 			continue
 		}
 
@@ -335,6 +335,11 @@ func validateListAnnotations(yamlStruct *k8sYamlStruct, manifest string) error {
 	return nil
 }
 
+func isYamlFileExtension(fileName string) bool {
+	ext := strings.ToLower(filepath.Ext(fileName))
+	return ext == ".yaml" || ext == ".yml"
+}
+
 // k8sYamlStruct stubs a Kubernetes YAML file.
 type k8sYamlStruct struct {
 	APIVersion string `json:"apiVersion"`
diff --git a/internal/chart/v3/lint/rules/template_test.go b/internal/chart/v3/lint/rules/template_test.go
index 40bcfa26b..d7665211a 100644
--- a/internal/chart/v3/lint/rules/template_test.go
+++ b/internal/chart/v3/lint/rules/template_test.go
@@ -439,3 +439,23 @@ items:
 		t.Fatalf("List objects keep annotations should pass. got: %s", err)
 	}
 }
+
+func TestIsYamlFileExtension(t *testing.T) {
+	tests := []struct {
+		filename string
+		expected bool
+	}{
+		{"test.yaml", true},
+		{"test.yml", true},
+		{"test.txt", false},
+		{"test", false},
+	}
+
+	for _, test := range tests {
+		result := isYamlFileExtension(test.filename)
+		if result != test.expected {
+			t.Errorf("isYamlFileExtension(%s) = %v; want %v", test.filename, result, test.expected)
+		}
+	}
+
+}
diff --git a/pkg/chart/v2/lint/rules/template.go b/pkg/chart/v2/lint/rules/template.go
index b21050a9e..0c633dc1a 100644
--- a/pkg/chart/v2/lint/rules/template.go
+++ b/pkg/chart/v2/lint/rules/template.go
@@ -156,7 +156,7 @@ func (t *templateLinter) Lint() {
 		t.linter.RunLinterRule(support.ErrorSev, fileName, validateAllowedExtension(fileName))
 
 		// We only apply the following lint rules to yaml files
-		if filepath.Ext(fileName) != ".yaml" || filepath.Ext(fileName) == ".yml" {
+		if !isYamlFileExtension(fileName) {
 			continue
 		}
 
@@ -366,6 +366,11 @@ func validateListAnnotations(yamlStruct *k8sYamlStruct, manifest string) error {
 	return nil
 }
 
+func isYamlFileExtension(fileName string) bool {
+	ext := strings.ToLower(filepath.Ext(fileName))
+	return ext == ".yaml" || ext == ".yml"
+}
+
 // k8sYamlStruct stubs a Kubernetes YAML file.
 type k8sYamlStruct struct {
 	APIVersion string `json:"apiVersion"`
diff --git a/pkg/chart/v2/lint/rules/template_test.go b/pkg/chart/v2/lint/rules/template_test.go
index 7629d3de5..7f9899070 100644
--- a/pkg/chart/v2/lint/rules/template_test.go
+++ b/pkg/chart/v2/lint/rules/template_test.go
@@ -462,3 +462,23 @@ items:
 		t.Fatalf("List objects keep annotations should pass. got: %s", err)
 	}
 }
+
+func TestIsYamlFileExtension(t *testing.T) {
+	tests := []struct {
+		filename string
+		expected bool
+	}{
+		{"test.yaml", true},
+		{"test.yml", true},
+		{"test.txt", false},
+		{"test", false},
+	}
+
+	for _, test := range tests {
+		result := isYamlFileExtension(test.filename)
+		if result != test.expected {
+			t.Errorf("isYamlFileExtension(%s) = %v; want %v", test.filename, result, test.expected)
+		}
+	}
+
+}