diff --git a/Misc/NEWS b/Misc/NEWS
index e70db5a9d3c..941eb29fd9c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -285,6 +285,8 @@ Tests
 Build
 -----
 
+- Issue #19520: Fix compiler warning in the _sha3 module on 32bit Windows.
+
 - Issue #19356: Avoid using a C variabled named "_self", it's a reserved
   word in some C compilers.
 
diff --git a/Modules/_sha3/keccak/KeccakF-1600-opt32.c b/Modules/_sha3/keccak/KeccakF-1600-opt32.c
index dba6d59f134..c52bfb7fd7c 100644
--- a/Modules/_sha3/keccak/KeccakF-1600-opt32.c
+++ b/Modules/_sha3/keccak/KeccakF-1600-opt32.c
@@ -212,7 +212,7 @@ static void setInterleavedWordsInto8bytes(UINT8* dest, UINT32* evenAndOdd)
 
 #define extractLanes(laneCount, state, data) \
     { \
-        int i; \
+        unsigned int i; \
         for(i=0; i<(laneCount); i++) \
             setInterleavedWordsInto8bytes(data+i*8, (UINT32*)state+i*2); \
     }