diff --git a/src/operators/rbl.cc b/src/operators/rbl.cc
index eb7c3f0b..f1561e7f 100644
--- a/src/operators/rbl.cc
+++ b/src/operators/rbl.cc
@@ -22,8 +22,8 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #else
-#include <winsock2.h>
-#include <ws2tcpip.h>
+#include <WinSock2.h>
+#include <WS2tcpip.h>
 #endif
 
 #include <string>
diff --git a/src/operators/rbl.h b/src/operators/rbl.h
index 7f70b599..30fcaa3e 100644
--- a/src/operators/rbl.h
+++ b/src/operators/rbl.h
@@ -23,7 +23,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #else
-#include <winsock2.h>
+#include <WinSock2.h>
 #endif
 
 #include <string>
diff --git a/src/unique_id.cc b/src/unique_id.cc
index c6234112..3106776e 100644
--- a/src/unique_id.cc
+++ b/src/unique_id.cc
@@ -18,7 +18,7 @@
 
 #ifdef WIN32
 #include "src/compat/msvc.h"
-#include <winsock2.h>
+#include <WinSock2.h>
 #include <iphlpapi.h>
 #endif
 
diff --git a/src/utils/geo_lookup.cc b/src/utils/geo_lookup.cc
index e76e728d..4e06a1ec 100644
--- a/src/utils/geo_lookup.cc
+++ b/src/utils/geo_lookup.cc
@@ -18,7 +18,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #else
-#include <winsock2.h>
+#include <WinSock2.h>
 #endif
 #include <string>
 
diff --git a/src/utils/https_client.cc b/src/utils/https_client.cc
index 66e818d4..f413e8ca 100644
--- a/src/utils/https_client.cc
+++ b/src/utils/https_client.cc
@@ -26,7 +26,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #else
-#include <winsock2.h>
+#include <WinSock2.h>
 #endif
 #include <string>
 
diff --git a/src/utils/ip_tree.cc b/src/utils/ip_tree.cc
index c4c38f1c..124bc47f 100644
--- a/src/utils/ip_tree.cc
+++ b/src/utils/ip_tree.cc
@@ -21,7 +21,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #else
-#include <winsock2.h>
+#include <WinSock2.h>
 #endif
 #include <string>
 
diff --git a/src/utils/msc_tree.cc b/src/utils/msc_tree.cc
index c2850750..27c7461c 100644
--- a/src/utils/msc_tree.cc
+++ b/src/utils/msc_tree.cc
@@ -21,8 +21,8 @@
 #include <arpa/inet.h>
 #else
 #include "src/compat/msvc.h"
-#include <winsock2.h>
-#include <ws2tcpip.h>
+#include <WinSock2.h>
+#include <WS2tcpip.h>
 #endif
 
 #include "src/utils/msc_tree.h"