diff --git a/icu4c/source/common/locid.cpp b/icu4c/source/common/locid.cpp
index 448c1de5e44..2d005b23542 100644
--- a/icu4c/source/common/locid.cpp
+++ b/icu4c/source/common/locid.cpp
@@ -1577,8 +1577,12 @@ AliasReplacer::replaceTransformedExtensions(
             tkey = nextTKey;
         } while (tkey != nullptr);
         tfields.sort([](UElement e1, UElement e2) -> int8_t {
-            return uprv_strcmp(
+            // uprv_strcmp return int and in some platform, such as arm64-v8a,
+            // it may return positive values > 127 which cause the casted value
+            // of int8_t negative.
+            int res = uprv_strcmp(
                 (const char*)e1.pointer, (const char*)e2.pointer);
+            return (res == 0) ? 0 : ((res > 0) ? 1 : -1);
         }, status);
         for (int32_t i = 0; i < tfields.size(); i++) {
              if (output.length() > 0) {
@@ -1618,8 +1622,12 @@ AliasReplacer::outputToString(
           out.append(SEP_CHAR, status);
         }
         variants.sort([](UElement e1, UElement e2) -> int8_t {
-            return uprv_strcmp(
+            // uprv_strcmp return int and in some platform, such as arm64-v8a,
+            // it may return positive values > 127 which cause the casted value
+            // of int8_t negative.
+            int res = uprv_strcmp(
                 (const char*)e1.pointer, (const char*)e2.pointer);
+            return (res == 0) ? 0 : ((res > 0) ? 1 : -1);
         }, status);
         int32_t variantsStart = out.length();
         for (int32_t i = 0; i < variants.size(); i++) {
@@ -1680,8 +1688,12 @@ AliasReplacer::replace(const Locale& locale, CharString& out, UErrorCode& status
 
     // Sort the variants
     variants.sort([](UElement e1, UElement e2) -> int8_t {
-        return uprv_strcmp(
+        // uprv_strcmp return int and in some platform, such as arm64-v8a,
+        // it may return positive values > 127 which cause the casted value
+        // of int8_t negative.
+        int res = uprv_strcmp(
             (const char*)e1.pointer, (const char*)e2.pointer);
+        return (res == 0) ? 0 : ((res > 0) ? 1 : -1);
     }, status);
 
     // A changed count to assert when loop too many times.