diff --git a/src/main/java/org/apache/commons/text/CaseUtils.java b/src/main/java/org/apache/commons/text/CaseUtils.java
index d079fb8b84..075903a948 100644
--- a/src/main/java/org/apache/commons/text/CaseUtils.java
+++ b/src/main/java/org/apache/commons/text/CaseUtils.java
@@ -17,6 +17,7 @@
 package org.apache.commons.text;
 
 import java.util.HashSet;
+import java.util.Locale;
 import java.util.Set;
 
 import org.apache.commons.lang3.ArrayUtils;
@@ -70,7 +71,7 @@ public static String toCamelCase(String str, final boolean capitalizeFirstLetter
         if (StringUtils.isEmpty(str)) {
             return str;
         }
-        str = str.toLowerCase();
+        str = str.toLowerCase(Locale.ROOT);
         final int strLen = str.length();
         final int[] newCodePoints = new int[strLen];
         int outOffset = 0;
diff --git a/src/main/java/org/apache/commons/text/WordUtils.java b/src/main/java/org/apache/commons/text/WordUtils.java
index 720ca5f98c..f76f028859 100644
--- a/src/main/java/org/apache/commons/text/WordUtils.java
+++ b/src/main/java/org/apache/commons/text/WordUtils.java
@@ -17,6 +17,7 @@
 package org.apache.commons.text;
 
 import java.util.HashSet;
+import java.util.Locale;
 import java.util.Set;
 import java.util.function.Predicate;
 import java.util.regex.Matcher;
@@ -250,7 +251,7 @@ public static String capitalizeFully(String str, final char... delimiters) {
         if (StringUtils.isEmpty(str)) {
             return str;
         }
-        str = str.toLowerCase();
+        str = str.toLowerCase(Locale.ROOT);
         return capitalize(str, delimiters);
     }
 
diff --git a/src/main/java/org/apache/commons/text/lookup/StringLookupFactory.java b/src/main/java/org/apache/commons/text/lookup/StringLookupFactory.java
index 699b7deab7..a9c7b0ba10 100644
--- a/src/main/java/org/apache/commons/text/lookup/StringLookupFactory.java
+++ b/src/main/java/org/apache/commons/text/lookup/StringLookupFactory.java
@@ -328,7 +328,7 @@ private static Map<String, StringLookup> parseStringLookups(final String str) {
             try {
                 for (final String lookupName : str.split("[\\s,]+")) {
                     if (!lookupName.isEmpty()) {
-                        addLookup(DefaultStringLookup.valueOf(lookupName.toUpperCase()), lookupMap);
+                        addLookup(DefaultStringLookup.valueOf(lookupName.toUpperCase(Locale.ROOT)), lookupMap);
                     }
                 }
             } catch (final IllegalArgumentException exc) {
diff --git a/src/test/java/org/apache/commons/text/CaseUtilsTest.java b/src/test/java/org/apache/commons/text/CaseUtilsTest.java
index 899e5e8d22..f9d7237d5b 100644
--- a/src/test/java/org/apache/commons/text/CaseUtilsTest.java
+++ b/src/test/java/org/apache/commons/text/CaseUtilsTest.java
@@ -26,6 +26,7 @@
 import java.lang.reflect.Modifier;
 
 import org.junit.jupiter.api.Test;
+import org.junitpioneer.jupiter.DefaultLocale;
 
 /**
  * Tests {@link CaseUtils} class.
@@ -77,4 +78,12 @@ void testToCamelCase() {
         assertEquals("\uD800\uDF00\uD800\uDF01\uD800\uDF02\uD800\uDF03",
                 CaseUtils.toCamelCase("\uD800\uDF00\uD800\uDF01\uD800\uDF14\uD800\uDF02\uD800\uDF03", true, '\uD800', '\uDF14'));
     }
+
+    @Test
+    @DefaultLocale(language = "tr", country = "TR")
+    void testToCamelCaseLocaleIndependent() {
+        // Turkish lower-cases 'I' (U+0049) to dotless 'i' (U+0131), which would otherwise leak into the result.
+        assertEquals("TipTop", CaseUtils.toCamelCase("TIP.TOP", true, '.'));
+        assertEquals("toCamelCase", CaseUtils.toCamelCase("TO CAMEL CASE", false, null));
+    }
 }
diff --git a/src/test/java/org/apache/commons/text/WordUtilsTest.java b/src/test/java/org/apache/commons/text/WordUtilsTest.java
index 429a8934ff..85b8d1d462 100644
--- a/src/test/java/org/apache/commons/text/WordUtilsTest.java
+++ b/src/test/java/org/apache/commons/text/WordUtilsTest.java
@@ -32,6 +32,7 @@
 import org.apache.commons.lang3.ArrayUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.junit.jupiter.api.Test;
+import org.junitpioneer.jupiter.DefaultLocale;
 
 /**
  * Tests {@link WordUtils}.
@@ -124,6 +125,14 @@ void testCapitalizeFully_String() {
 
     }
 
+    @Test
+    @DefaultLocale(language = "tr", country = "TR")
+    void testCapitalizeFully_LocaleIndependent() {
+        // Turkish lower-cases 'I' (U+0049) to dotless 'i' (U+0131), which would otherwise leak into the result.
+        assertEquals("Heli World", WordUtils.capitalizeFully("HELI WORLD"));
+        assertEquals("I Am Here 123", WordUtils.capitalizeFully("I AM HERE 123"));
+    }
+
     @Test
     void testCapitalizeFully_Text88() {
         assertEquals("I am fine now", WordUtils.capitalizeFully("i am fine now", new char[] {}));
diff --git a/src/test/java/org/apache/commons/text/lookup/StringLookupFactoryTest.java b/src/test/java/org/apache/commons/text/lookup/StringLookupFactoryTest.java
index caeccd8289..e0fdf8abe7 100644
--- a/src/test/java/org/apache/commons/text/lookup/StringLookupFactoryTest.java
+++ b/src/test/java/org/apache/commons/text/lookup/StringLookupFactoryTest.java
@@ -32,6 +32,7 @@
 import javax.xml.XMLConstants;
 
 import org.junit.jupiter.api.Test;
+import org.junitpioneer.jupiter.DefaultLocale;
 import org.junitpioneer.jupiter.SetSystemProperty;
 
 /**
@@ -173,6 +174,16 @@ void testDefaultStringLookupsHolder_givenSingleLookup() {
         checkDefaultStringLookupsHolder(props, "base64", StringLookupFactory.KEY_BASE64_ENCODER);
     }
 
+    @Test
+    @DefaultLocale(language = "tr", country = "TR")
+    void testDefaultStringLookupsHolder_givenSingleLookup_localeIndependent() {
+        // Turkish upper-cases 'i' (U+0069) to dotted 'İ' (U+0130), so "file" would fold to "FİLE"
+        // and fail to resolve against the DefaultStringLookup enum without Locale.ROOT.
+        final Properties props = new Properties();
+        props.setProperty(StringLookupFactory.DEFAULT_STRING_LOOKUPS_PROPERTY, "file");
+        checkDefaultStringLookupsHolder(props, StringLookupFactory.KEY_FILE);
+    }
+
     @Test
     void testDefaultStringLookupsHolder_givenSingleLookup_weirdString() {
         final Properties props = new Properties();