diff --git a/src/colorprint.cc b/src/colorprint.cc
index 2dec4a8b..fff6a988 100644
--- a/src/colorprint.cc
+++ b/src/colorprint.cc
@@ -25,7 +25,7 @@
 #include "internal_macros.h"
 
 #ifdef BENCHMARK_OS_WINDOWS
-#include <Windows.h>
+#include <windows.h>
 #include <io.h>
 #else
 #include <unistd.h>
diff --git a/src/sleep.cc b/src/sleep.cc
index 54aa04a4..1512ac90 100644
--- a/src/sleep.cc
+++ b/src/sleep.cc
@@ -21,7 +21,7 @@
 #include "internal_macros.h"
 
 #ifdef BENCHMARK_OS_WINDOWS
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 namespace benchmark {
diff --git a/src/sysinfo.cc b/src/sysinfo.cc
index f79412b5..d4e5336f 100644
--- a/src/sysinfo.cc
+++ b/src/sysinfo.cc
@@ -15,10 +15,10 @@
 #include "internal_macros.h"
 
 #ifdef BENCHMARK_OS_WINDOWS
-#include <Shlwapi.h>
+#include <shlwapi.h>
 #undef StrCat  // Don't let StrCat in string_util.h be renamed to lstrcatA
-#include <VersionHelpers.h>
-#include <Windows.h>
+#include <versionhelpers.h>
+#include <windows.h>
 #else
 #include <fcntl.h>
 #ifndef BENCHMARK_OS_FUCHSIA
diff --git a/src/timers.cc b/src/timers.cc
index 2010e245..7613ff92 100644
--- a/src/timers.cc
+++ b/src/timers.cc
@@ -16,10 +16,10 @@
 #include "internal_macros.h"
 
 #ifdef BENCHMARK_OS_WINDOWS
-#include <Shlwapi.h>
+#include <shlwapi.h>
 #undef StrCat  // Don't let StrCat in string_util.h be renamed to lstrcatA
-#include <VersionHelpers.h>
-#include <Windows.h>
+#include <versionhelpers.h>
+#include <windows.h>
 #else
 #include <fcntl.h>
 #ifndef BENCHMARK_OS_FUCHSIA