diff --git a/icu4c/source/test/cintltst/ccapitst.c b/icu4c/source/test/cintltst/ccapitst.c
index 4a300faec1..5e7be8488f 100644
--- a/icu4c/source/test/cintltst/ccapitst.c
+++ b/icu4c/source/test/cintltst/ccapitst.c
@@ -3266,28 +3266,28 @@ InvalidArguments() {
 
     errorCode=U_ZERO_ERROR;
     /* This one should fail because an incomplete UChar is being passed in */
-    ucnv_fromUnicode(cnv, &charsPtr, charsPtr, &ucharsPtr, ucharsBadPtr, NULL, TRUE, &errorCode);
+    ucnv_fromUnicode(cnv, &charsPtr, charsPtr, (const UChar **)&ucharsPtr, ucharsBadPtr, NULL, TRUE, &errorCode);
     if(errorCode != U_ILLEGAL_ARGUMENT_ERROR) {
         log_err("ucnv_fromUnicode() failed to return U_ILLEGAL_ARGUMENT_ERROR for incomplete UChar * buffer - %s\n", u_errorName(errorCode));
     }
 
     errorCode=U_ZERO_ERROR;
     /* This one should fail because ucharsBadPtr is > than ucharsPtr */
-    ucnv_fromUnicode(cnv, &charsPtr, charsPtr, &ucharsBadPtr, ucharsPtr, NULL, TRUE, &errorCode);
+    ucnv_fromUnicode(cnv, &charsPtr, charsPtr, (const UChar **)&ucharsBadPtr, ucharsPtr, NULL, TRUE, &errorCode);
     if(errorCode != U_ILLEGAL_ARGUMENT_ERROR) {
         log_err("ucnv_fromUnicode() failed to return U_ILLEGAL_ARGUMENT_ERROR for bad limit pointer - %s\n", u_errorName(errorCode));
     }
 
     errorCode=U_ZERO_ERROR;
     /* This one should fail because an incomplete UChar is being passed in */
-    ucnv_toUnicode(cnv, &ucharsPtr, ucharsBadPtr, &charsPtr, charsPtr, NULL, TRUE, &errorCode);
+    ucnv_toUnicode(cnv, &ucharsPtr, ucharsBadPtr, (const char **)&charsPtr, charsPtr, NULL, TRUE, &errorCode);
     if(errorCode != U_ILLEGAL_ARGUMENT_ERROR) {
         log_err("ucnv_toUnicode() failed to return U_ILLEGAL_ARGUMENT_ERROR for incomplete UChar * buffer - %s\n", u_errorName(errorCode));
     }
 
     errorCode=U_ZERO_ERROR;
     /* This one should fail because ucharsBadPtr is > than ucharsPtr */
-    ucnv_toUnicode(cnv, &ucharsBadPtr, ucharsPtr, &charsPtr, charsPtr, NULL, TRUE, &errorCode);
+    ucnv_toUnicode(cnv, &ucharsBadPtr, ucharsPtr, (const char **)&charsPtr, charsPtr, NULL, TRUE, &errorCode);
     if(errorCode != U_ILLEGAL_ARGUMENT_ERROR) {
         log_err("ucnv_toUnicode() failed to return U_ILLEGAL_ARGUMENT_ERROR for bad limit pointer - %s\n", u_errorName(errorCode));
     }
diff --git a/icu4c/source/test/intltest/ustrtest.cpp b/icu4c/source/test/intltest/ustrtest.cpp
index 9aa8bfa87a..51af4b4e5d 100644
--- a/icu4c/source/test/intltest/ustrtest.cpp
+++ b/icu4c/source/test/intltest/ustrtest.cpp
@@ -1673,8 +1673,9 @@ namespace bogus {
     public:
         enum EInvariant { kInvariant };
         UnicodeString() : i(1) {}
-        UnicodeString(UBool isTerminated, const UChar *text, int32_t textLength) : i(textLength) {}
-        UnicodeString(const char *src, int32_t length, enum EInvariant inv) : i(length) {}
+        UnicodeString(UBool /*isTerminated*/, const UChar * /*text*/, int32_t textLength) : i(textLength) {}
+        UnicodeString(const char * /*src*/, int32_t length, enum EInvariant /*inv*/
+) : i(length) {}
     private:
         int32_t i;
     };