diff --git a/icu4c/source/common/locmap.cpp b/icu4c/source/common/locmap.cpp
index 3ca00757628..eda04e57df0 100644
--- a/icu4c/source/common/locmap.cpp
+++ b/icu4c/source/common/locmap.cpp
@@ -1116,7 +1116,7 @@ uprv_convertToPosix(uint32_t hostid, char *posixID, int32_t posixIDCapacity, UEr
         // Note: LOCALE_ALLOW_NEUTRAL_NAMES was enabled in Windows7+, prior versions did not handle neutral (no-region) locale names.
         tmpLen = LCIDToLocaleName(hostid, (PWSTR)windowsLocaleName, UPRV_LENGTHOF(windowsLocaleName), LOCALE_ALLOW_NEUTRAL_NAMES);
         if (tmpLen > 1) {
-            int i = 0;
+            int32_t i = 0;
             // Only need to look up in table if have _, eg for de-de_phoneb type alternate sort.
             bLookup = FALSE;
             for (i = 0; i < UPRV_LENGTHOF(locName); i++)
@@ -1253,7 +1253,7 @@ uprv_convertToLCIDPlatform(const char* localeID)
     {
         // Need it to be UTF-16, not 8-bit
         wchar_t bcp47Tag[LOCALE_NAME_MAX_LENGTH] = {};
-        int i;
+        int32_t i;
         for (i = 0; i < UPRV_LENGTHOF(bcp47Tag); i++)
         {
             if (asciiBCP47Tag[i] == '\0')
diff --git a/icu4c/source/common/putil.cpp b/icu4c/source/common/putil.cpp
index 70618751ab9..011e6e178f8 100644
--- a/icu4c/source/common/putil.cpp
+++ b/icu4c/source/common/putil.cpp
@@ -1781,7 +1781,7 @@ The leftmost codepage (.xxx) wins.
         // First we need to go from UTF-16 to char (and also convert from _ to - while we're at it.)
         char modifiedWindowsLocale[LOCALE_NAME_MAX_LENGTH];
 
-        int i;
+        int32_t i;
         for (i = 0; i < UPRV_LENGTHOF(modifiedWindowsLocale); i++)
         {
             if (windowsLocale[i] == '_')
diff --git a/icu4c/source/common/umapfile.cpp b/icu4c/source/common/umapfile.cpp
index bfa9b1b7190..df588a4f950 100644
--- a/icu4c/source/common/umapfile.cpp
+++ b/icu4c/source/common/umapfile.cpp
@@ -117,7 +117,7 @@
         // First we need to go from char to UTF-16
         // u_UCharsToChars could work but it requires length.
         WCHAR utf16Path[MAX_PATH];
-        int i;
+        int32_t i;
         for (i = 0; i < UPRV_LENGTHOF(utf16Path); i++)
         {
             utf16Path[i] = path[i];
diff --git a/icu4c/source/i18n/windtfmt.cpp b/icu4c/source/i18n/windtfmt.cpp
index f9b575f8ab0..d0599ab5147 100644
--- a/icu4c/source/i18n/windtfmt.cpp
+++ b/icu4c/source/i18n/windtfmt.cpp
@@ -109,7 +109,7 @@ static UErrorCode GetEquivalentWindowsLocaleName(const Locale& locale, UnicodeSt
         // Need it to be UTF-16, not 8-bit
         // TODO: This seems like a good thing for a helper
         wchar_t bcp47Tag[LOCALE_NAME_MAX_LENGTH] = {};
-        int i;
+        int32_t i;
         for (i = 0; i < UPRV_LENGTHOF(bcp47Tag); i++)
         {
             if (asciiBCP47Tag[i] == '\0')
diff --git a/icu4c/source/i18n/winnmfmt.cpp b/icu4c/source/i18n/winnmfmt.cpp
index 3f8271efaf0..3e03cb1feef 100644
--- a/icu4c/source/i18n/winnmfmt.cpp
+++ b/icu4c/source/i18n/winnmfmt.cpp
@@ -154,7 +154,7 @@ static UErrorCode GetEquivalentWindowsLocaleName(const Locale& locale, UnicodeSt
         // Need it to be UTF-16, not 8-bit
         // TODO: This seems like a good thing for a helper
         wchar_t bcp47Tag[LOCALE_NAME_MAX_LENGTH] = {};
-        int i;
+        int32_t i;
         for (i = 0; i < UPRV_LENGTHOF(bcp47Tag); i++)
         {
             if (asciiBCP47Tag[i] == '\0')