diff --git a/SUPPORTED_PLATFORMS.md b/SUPPORTED_PLATFORMS.md
index 2c678629..9597801b 100644
--- a/SUPPORTED_PLATFORMS.md
+++ b/SUPPORTED_PLATFORMS.md
@@ -11,7 +11,7 @@
 | z/OS | Tier 2 | >= V2R2 | Maintainers: @libuv/zos |
 | Linux with musl | Tier 2 | musl >= 1.0 | |
 | Android | Tier 3 | NDK >= r15b | Android 7.0, `-DANDROID_PLATFORM=android-24` |
-| MinGW | Tier 3 | MinGW32 and MinGW-w64 | |
+| MinGW | Tier 3 | MinGW-w64 | |
 | SunOS | Tier 3 | Solaris 121 and later | |
 | Other | Tier 3 | N/A | |
 
diff --git a/include/uv/win.h b/include/uv/win.h
index be17faec..58d10b8d 100644
--- a/include/uv/win.h
+++ b/include/uv/win.h
@@ -32,14 +32,6 @@ typedef intptr_t ssize_t;
 
 #include <winsock2.h>
 
-#if defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
-typedef struct pollfd {
-  SOCKET fd;
-  short  events;
-  short  revents;
-} WSAPOLLFD, *PWSAPOLLFD, *LPWSAPOLLFD;
-#endif
-
 #ifndef LOCALE_INVARIANT
 # define LOCALE_INVARIANT 0x007f
 #endif
diff --git a/src/win/winapi.h b/src/win/winapi.h
index d52ad9b3..aa68fcd5 100644
--- a/src/win/winapi.h
+++ b/src/win/winapi.h
@@ -4150,40 +4150,35 @@ typedef struct _FILE_STAT_BASIC_INFORMATION {
 } FILE_STAT_BASIC_INFORMATION;
 #endif
 
-/* MinGW already has a definition for REPARSE_DATA_BUFFER, but mingw-w64 does
- * not.
- */
-#if defined(_MSC_VER) || defined(__MINGW64_VERSION_MAJOR)
-  typedef struct _REPARSE_DATA_BUFFER {
-    ULONG  ReparseTag;
-    USHORT ReparseDataLength;
-    USHORT Reserved;
-    union {
-      struct {
-        USHORT SubstituteNameOffset;
-        USHORT SubstituteNameLength;
-        USHORT PrintNameOffset;
-        USHORT PrintNameLength;
-        ULONG Flags;
-        WCHAR PathBuffer[1];
-      } SymbolicLinkReparseBuffer;
-      struct {
-        USHORT SubstituteNameOffset;
-        USHORT SubstituteNameLength;
-        USHORT PrintNameOffset;
-        USHORT PrintNameLength;
-        WCHAR PathBuffer[1];
-      } MountPointReparseBuffer;
-      struct {
-        UCHAR  DataBuffer[1];
-      } GenericReparseBuffer;
-      struct {
-        ULONG StringCount;
-        WCHAR StringList[1];
-      } AppExecLinkReparseBuffer;
-    };
-  } REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
-#endif
+typedef struct _REPARSE_DATA_BUFFER {
+  ULONG  ReparseTag;
+  USHORT ReparseDataLength;
+  USHORT Reserved;
+  union {
+    struct {
+      USHORT SubstituteNameOffset;
+      USHORT SubstituteNameLength;
+      USHORT PrintNameOffset;
+      USHORT PrintNameLength;
+      ULONG Flags;
+      WCHAR PathBuffer[1];
+    } SymbolicLinkReparseBuffer;
+    struct {
+      USHORT SubstituteNameOffset;
+      USHORT SubstituteNameLength;
+      USHORT PrintNameOffset;
+      USHORT PrintNameLength;
+      WCHAR PathBuffer[1];
+    } MountPointReparseBuffer;
+    struct {
+      UCHAR  DataBuffer[1];
+    } GenericReparseBuffer;
+    struct {
+      ULONG StringCount;
+      WCHAR StringList[1];
+    } AppExecLinkReparseBuffer;
+  };
+} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
 
 typedef struct _IO_STATUS_BLOCK {
   union {
@@ -4661,15 +4656,6 @@ typedef NTSTATUS (NTAPI *sNtQueryInformationProcess)
 # define SYMBOLIC_LINK_FLAG_DIRECTORY 0x1
 #endif
 
-#if defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
-  typedef struct _OVERLAPPED_ENTRY {
-      ULONG_PTR lpCompletionKey;
-      LPOVERLAPPED lpOverlapped;
-      ULONG_PTR Internal;
-      DWORD dwNumberOfBytesTransferred;
-  } OVERLAPPED_ENTRY, *LPOVERLAPPED_ENTRY;
-#endif
-
 /* from wincon.h */
 #ifndef ENABLE_INSERT_MODE
 # define ENABLE_INSERT_MODE 0x20
diff --git a/src/win/winsock.h b/src/win/winsock.h
index 2af95887..bb3808a3 100644
--- a/src/win/winsock.h
+++ b/src/win/winsock.h
@@ -154,47 +154,6 @@ typedef struct _AFD_RECV_INFO {
 #define IOCTL_AFD_POLL \
     _AFD_CONTROL_CODE(AFD_POLL, METHOD_BUFFERED)
 
-#if defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
-typedef struct _IP_ADAPTER_UNICAST_ADDRESS_XP {
-  /* FIXME: __C89_NAMELESS was removed */
-  /* __C89_NAMELESS */ union {
-    ULONGLONG Alignment;
-    /* __C89_NAMELESS */ struct {
-      ULONG Length;
-      DWORD Flags;
-    };
-  };
-  struct _IP_ADAPTER_UNICAST_ADDRESS_XP *Next;
-  SOCKET_ADDRESS Address;
-  IP_PREFIX_ORIGIN PrefixOrigin;
-  IP_SUFFIX_ORIGIN SuffixOrigin;
-  IP_DAD_STATE DadState;
-  ULONG ValidLifetime;
-  ULONG PreferredLifetime;
-  ULONG LeaseLifetime;
-} IP_ADAPTER_UNICAST_ADDRESS_XP,*PIP_ADAPTER_UNICAST_ADDRESS_XP;
-
-typedef struct _IP_ADAPTER_UNICAST_ADDRESS_LH {
-  union {
-    ULONGLONG Alignment;
-    struct {
-      ULONG Length;
-      DWORD Flags;
-    };
-  };
-  struct _IP_ADAPTER_UNICAST_ADDRESS_LH *Next;
-  SOCKET_ADDRESS Address;
-  IP_PREFIX_ORIGIN PrefixOrigin;
-  IP_SUFFIX_ORIGIN SuffixOrigin;
-  IP_DAD_STATE DadState;
-  ULONG ValidLifetime;
-  ULONG PreferredLifetime;
-  ULONG LeaseLifetime;
-  UINT8 OnLinkPrefixLength;
-} IP_ADAPTER_UNICAST_ADDRESS_LH,*PIP_ADAPTER_UNICAST_ADDRESS_LH;
-
-#endif
-
 int uv__convert_to_localhost_if_unspecified(const struct sockaddr* addr,
                                             struct sockaddr_storage* storage);
 
diff --git a/test/test-spawn.c b/test/test-spawn.c
index efbb2395..964c8a86 100644
--- a/test/test-spawn.c
+++ b/test/test-spawn.c
@@ -1329,9 +1329,7 @@ TEST_IMPL(environment_creation) {
       }
     }
     if (prev) { /* verify sort order */
-#if !defined(__MINGW32__) || defined(__MINGW64_VERSION_MAJOR)
       ASSERT_EQ(1, CompareStringOrdinal(prev, -1, str, -1, TRUE));
-#endif
     }
     ASSERT(found); /* verify that we expected this variable */
   }
@@ -1524,7 +1522,7 @@ TEST_IMPL(spawn_setuid_fails) {
   init_process_options("spawn_helper1", fail_cb);
 
   options.flags |= UV_PROCESS_SETUID;
-  /* On IBMi PASE, there is no root user. User may grant 
+  /* On IBMi PASE, there is no root user. User may grant
    * root-like privileges, including setting uid to 0.
    */
 #if defined(__PASE__)
@@ -1575,7 +1573,7 @@ TEST_IMPL(spawn_setgid_fails) {
   init_process_options("spawn_helper1", fail_cb);
 
   options.flags |= UV_PROCESS_SETGID;
-  /* On IBMi PASE, there is no root user. User may grant 
+  /* On IBMi PASE, there is no root user. User may grant
    * root-like privileges, including setting gid to 0.
    */
 #if defined(__MVS__) || defined(__PASE__)