diff --git a/Foundation/org.egovframe.rte.fdl.string/src/main/java/org/egovframe/rte/fdl/string/EgovStringUtil.java b/Foundation/org.egovframe.rte.fdl.string/src/main/java/org/egovframe/rte/fdl/string/EgovStringUtil.java
index 4e280948..6ec761be 100755
--- a/Foundation/org.egovframe.rte.fdl.string/src/main/java/org/egovframe/rte/fdl/string/EgovStringUtil.java
+++ b/Foundation/org.egovframe.rte.fdl.string/src/main/java/org/egovframe/rte/fdl/string/EgovStringUtil.java
@@ -25,6 +25,7 @@
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.StringTokenizer;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -990,7 +991,7 @@ public static List<?> getTokens(String lst) {
     public static String convertToCamelCase(String targetString, char posChar) {
         StringBuilder result = new StringBuilder();
         boolean nextUpper = false;
-        String allLower = targetString.toLowerCase();
+        String allLower = targetString.toLowerCase(Locale.ROOT);
         for (int i = 0; i < allLower.length(); i++) {
             char currentChar = allLower.charAt(i);
             if (currentChar == posChar) {
@@ -1029,7 +1030,7 @@ public static String convertToUnderScore(String camelCase) {
             if (i > 0 && Character.isUpperCase(currentChar)) {
                 result = result.concat("_");
             }
-            result = result.concat(Character.toString(currentChar).toLowerCase());
+            result = result.concat(Character.toString(currentChar).toLowerCase(Locale.ROOT));
         }
         return result;
     }
diff --git a/Foundation/org.egovframe.rte.fdl.string/src/test/java/org/egovframe/rte/fdl/string/EgovStringUtilLocaleTest.java b/Foundation/org.egovframe.rte.fdl.string/src/test/java/org/egovframe/rte/fdl/string/EgovStringUtilLocaleTest.java
new file mode 100644
index 00000000..b47ab019
--- /dev/null
+++ b/Foundation/org.egovframe.rte.fdl.string/src/test/java/org/egovframe/rte/fdl/string/EgovStringUtilLocaleTest.java
@@ -0,0 +1,44 @@
+package org.egovframe.rte.fdl.string;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.Locale;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * 식별자 변환 메서드들이 JVM 기본 로케일과 무관하게 동작하는지 검증한다.
+ *
+ * <p>터키어·아제르바이잔어 로케일에서는 인자 없는 toUpperCase()/toLowerCase()가
+ * i ↔ İ(U+0130) / I ↔ ı(U+0131)로 변환한다. 같은 저장소의 CamelCaseUtil은
+ * Character 단위 변환을 써서 이 문제가 없다.</p>
+ */
+public class EgovStringUtilLocaleTest {
+
+    private void underTurkishLocale(Runnable body) {
+        Locale original = Locale.getDefault();
+        try {
+            Locale.setDefault(Locale.forLanguageTag("tr-TR"));
+            body.run();
+        } finally {
+            Locale.setDefault(original);
+        }
+    }
+
+    @Test
+    @DisplayName("convertToCamelCase는 로케일과 무관하게 ASCII 규칙으로 변환한다")
+    public void convertToCamelCaseIsLocaleIndependent() {
+        underTurkishLocale(() ->
+                assertEquals("printStatus", EgovStringUtil.convertToCamelCase("PRINT_STATUS", '_')));
+        assertEquals("printStatus", EgovStringUtil.convertToCamelCase("PRINT_STATUS", '_'));
+    }
+
+    @Test
+    @DisplayName("convertToUnderScore는 로케일과 무관하게 ASCII 규칙으로 변환한다")
+    public void convertToUnderScoreIsLocaleIndependent() {
+        underTurkishLocale(() ->
+                assertEquals("print_id", EgovStringUtil.convertToUnderScore("printId")));
+        assertEquals("print_id", EgovStringUtil.convertToUnderScore("printId"));
+    }
+}