diff --git a/src/libexpr/lexer-helpers.hh b/src/libexpr/lexer-helpers.hh
index b4a166f46a8..d40f7b874e8 100644
--- a/src/libexpr/lexer-helpers.hh
+++ b/src/libexpr/lexer-helpers.hh
@@ -4,8 +4,8 @@
 
 // inluding the generated headers twice leads to errors
 #ifndef BISON_HEADER
-#include "lexer-tab.hh"
-#include "parser-tab.hh"
+#  include "lexer-tab.hh"
+#  include "parser-tab.hh"
 #endif
 
 namespace nix::lexer::internal {
diff --git a/src/libstore/windows/pathlocks.cc b/src/libstore/windows/pathlocks.cc
index 00761a8c33c..197f5a1c46d 100644
--- a/src/libstore/windows/pathlocks.cc
+++ b/src/libstore/windows/pathlocks.cc
@@ -2,10 +2,12 @@
 #include "pathlocks.hh"
 #include "signals.hh"
 #include "util.hh"
-#include <errhandlingapi.h>
-#include <fileapi.h>
-#include <windows.h>
-#include "windows-error.hh"
+
+#ifdef WIN32
+#  include <errhandlingapi.h>
+#  include <fileapi.h>
+#  include <windows.h>
+#  include "windows-error.hh"
 
 namespace nix {
 
@@ -154,3 +156,4 @@ FdLock::FdLock(Descriptor desc, LockType lockType, bool wait, std::string_view w
 }
 
 }
+#endif
diff --git a/src/libutil/windows/environment-variables.cc b/src/libutil/windows/environment-variables.cc
index 5ce8a139537..308a432e4d8 100644
--- a/src/libutil/windows/environment-variables.cc
+++ b/src/libutil/windows/environment-variables.cc
@@ -1,6 +1,7 @@
 #include "environment-variables.hh"
 
-#include "processenv.h"
+#ifdef WIN32
+#  include "processenv.h"
 
 namespace nix {
 
@@ -43,3 +44,4 @@ int setEnvOs(const OsString & name, const OsString & value)
 }
 
 }
+#endif
diff --git a/src/libutil/windows/file-descriptor.cc b/src/libutil/windows/file-descriptor.cc
index 7b8a712e879..71f53ccb886 100644
--- a/src/libutil/windows/file-descriptor.cc
+++ b/src/libutil/windows/file-descriptor.cc
@@ -5,6 +5,7 @@
 #include "windows-error.hh"
 #include "file-path.hh"
 
+#ifdef WIN32
 #include <fileapi.h>
 #include <error.h>
 #include <namedpipeapi.h>
@@ -152,3 +153,4 @@ Path windows::handleToPath(HANDLE handle) {
 #endif
 
 }
+#endif
diff --git a/src/libutil/windows/file-system.cc b/src/libutil/windows/file-system.cc
index b15355efe88..53271cef3da 100644
--- a/src/libutil/windows/file-system.cc
+++ b/src/libutil/windows/file-system.cc
@@ -1,5 +1,6 @@
 #include "file-system.hh"
 
+#ifdef WIN32
 namespace nix {
 
 Descriptor openDirectory(const std::filesystem::path & path)
@@ -15,3 +16,4 @@ Descriptor openDirectory(const std::filesystem::path & path)
 }
 
 }
+#endif
diff --git a/src/libutil/windows/muxable-pipe.cc b/src/libutil/windows/muxable-pipe.cc
index 91a321f7cfa..af7e987e9f2 100644
--- a/src/libutil/windows/muxable-pipe.cc
+++ b/src/libutil/windows/muxable-pipe.cc
@@ -1,9 +1,10 @@
-#include <ioapiset.h>
-#include "windows-error.hh"
+#ifdef WIN32
+#  include <ioapiset.h>
+#  include "windows-error.hh"
 
-#include "logging.hh"
-#include "util.hh"
-#include "muxable-pipe.hh"
+#  include "logging.hh"
+#  include "util.hh"
+#  include "muxable-pipe.hh"
 
 namespace nix {
 
@@ -68,3 +69,4 @@ void MuxablePipePollState::iterate(
 }
 
 }
+#endif
diff --git a/src/libutil/windows/os-string.cc b/src/libutil/windows/os-string.cc
index 7507f9030da..26ad9cba0c8 100644
--- a/src/libutil/windows/os-string.cc
+++ b/src/libutil/windows/os-string.cc
@@ -7,6 +7,8 @@
 #include "file-path-impl.hh"
 #include "util.hh"
 
+#ifdef WIN32
+
 namespace nix {
 
 std::string os_string_to_string(PathViewNG::string_view path)
@@ -22,3 +24,5 @@ std::filesystem::path::string_type string_to_os_string(std::string_view s)
 }
 
 }
+
+#endif
diff --git a/src/libutil/windows/processes.cc b/src/libutil/windows/processes.cc
index 7f34c5632e8..e69f1ed45a5 100644
--- a/src/libutil/windows/processes.cc
+++ b/src/libutil/windows/processes.cc
@@ -23,6 +23,8 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#ifdef WIN32
+
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 
@@ -386,3 +388,5 @@ int execvpe(const wchar_t * file0, const wchar_t * const argv[], const wchar_t *
 }
 
 }
+
+#endif
diff --git a/src/libutil/windows/users.cc b/src/libutil/windows/users.cc
index db6c42df381..2780e45f4a1 100644
--- a/src/libutil/windows/users.cc
+++ b/src/libutil/windows/users.cc
@@ -4,6 +4,7 @@
 #include "file-system.hh"
 #include "windows-error.hh"
 
+#ifdef WIN32
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 
@@ -50,3 +51,4 @@ bool isRootUser() {
 }
 
 }
+#endif
diff --git a/src/libutil/windows/windows-async-pipe.cc b/src/libutil/windows/windows-async-pipe.cc
index 4fa57ca3672..13b56351029 100644
--- a/src/libutil/windows/windows-async-pipe.cc
+++ b/src/libutil/windows/windows-async-pipe.cc
@@ -1,6 +1,8 @@
 #include "windows-async-pipe.hh"
 #include "windows-error.hh"
 
+#ifdef WIN32
+
 namespace nix::windows {
 
 void AsyncPipe::createAsyncPipe(HANDLE iocp)
@@ -47,3 +49,5 @@ void AsyncPipe::close()
 }
 
 }
+
+#endif
diff --git a/src/libutil/windows/windows-async-pipe.hh b/src/libutil/windows/windows-async-pipe.hh
index 8f554e403f3..277336ed76a 100644
--- a/src/libutil/windows/windows-async-pipe.hh
+++ b/src/libutil/windows/windows-async-pipe.hh
@@ -2,6 +2,7 @@
 ///@file
 
 #include "file-descriptor.hh"
+#ifdef WIN32
 
 namespace nix::windows {
 
@@ -25,3 +26,4 @@ public:
 };
 
 }
+#endif
diff --git a/src/libutil/windows/windows-error.cc b/src/libutil/windows/windows-error.cc
index aead4af2378..4cf4274dae7 100644
--- a/src/libutil/windows/windows-error.cc
+++ b/src/libutil/windows/windows-error.cc
@@ -1,5 +1,6 @@
 #include "windows-error.hh"
 
+#ifdef WIN32
 #include <error.h>
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
@@ -29,3 +30,4 @@ std::string WinError::renderError(DWORD lastError)
 }
 
 }
+#endif
diff --git a/src/libutil/windows/windows-error.hh b/src/libutil/windows/windows-error.hh
index 624b4c4cb0b..4e48ee8599c 100644
--- a/src/libutil/windows/windows-error.hh
+++ b/src/libutil/windows/windows-error.hh
@@ -1,6 +1,7 @@
 #pragma once
 ///@file
 
+#ifdef WIN32
 #include <errhandlingapi.h>
 
 #include "error.hh"
@@ -49,3 +50,4 @@ private:
 };
 
 }
+#endif