diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.append.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.append.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.append.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.append.pass.cpp
@@ -29,6 +29,10 @@
 #include <string_view>
 #include <cassert>
 
+// On Windows, the append function converts all inputs (pointers, iterators)
+// to an intermediate path object, causing allocations in cases where no
+// allocations are done on other platforms.
+
 #include "test_macros.h"
 #include "test_iterators.h"
 #include "count_new.h"
@@ -141,7 +145,7 @@
     path LHS(L); PathReserve(LHS, ReserveSize);
     Str  RHS(R);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       LHS /= RHS;
     }
     assert(PathEq(LHS, E));
@@ -151,7 +155,7 @@
     path LHS(L); PathReserve(LHS, ReserveSize);
     StrView  RHS(R);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       LHS /= RHS;
     }
     assert(PathEq(LHS, E));
@@ -161,7 +165,7 @@
     path LHS(L); PathReserve(LHS, ReserveSize);
     Ptr RHS(R);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       LHS /= RHS;
     }
     assert(PathEq(LHS, E));
@@ -170,7 +174,7 @@
     path LHS(L); PathReserve(LHS, ReserveSize);
     Ptr RHS(R);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       LHS.append(RHS, StrEnd(RHS));
     }
     assert(PathEq(LHS, E));
@@ -180,7 +184,13 @@
   // code_cvt conversions.
   // For "char" no allocations will be performed because no conversion is
   // required.
+  // On Windows, the append method is more complex and uses intermediate
+  // path objects, which causes extra allocations.
+#ifdef _WIN32
+  bool DisableAllocations = false;
+#else
   bool DisableAllocations = std::is_same<CharT, char>::value;
+#endif
   {
     path LHS(L); PathReserve(LHS, ReserveSize);
     InputIter RHS(R);
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/source.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/source.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/source.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.assign/source.pass.cpp
@@ -29,6 +29,9 @@
 #include <string_view>
 #include <cassert>
 
+// On Windows, charset conversions cause allocations in the path class in
+// cases where no allocations are done on other platforms.
+
 #include "test_macros.h"
 #include "test_iterators.h"
 #include "count_new.h"
@@ -51,7 +54,7 @@
     path p; PathReserve(p, S.length() + 1);
     {
       // string provides a contiguous iterator. No allocation needed.
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       path& pref = (p = S);
       assert(&pref == &p);
     }
@@ -63,7 +66,7 @@
     const std::basic_string<CharT> S(TestPath);
     path p; PathReserve(p, S.length() + 1);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       path& pref = p.assign(S);
       assert(&pref == &p);
     }
@@ -77,7 +80,7 @@
     path p; PathReserve(p, S.length() + 1);
     {
       // string provides a contiguous iterator. No allocation needed.
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       path& pref = (p = S);
       assert(&pref == &p);
     }
@@ -89,7 +92,7 @@
     const std::basic_string_view<CharT> S(TestPath);
     path p; PathReserve(p, S.length() + 1);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       path& pref = p.assign(S);
       assert(&pref == &p);
     }
@@ -104,7 +107,7 @@
     {
       // char* pointers are contiguous and can be used with code_cvt directly.
       // no allocations needed.
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       path& pref = (p = TestPath);
       assert(&pref == &p);
     }
@@ -114,7 +117,7 @@
   {
     path p; PathReserve(p, Size + 1);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       path& pref = p.assign(TestPath);
       assert(&pref == &p);
     }
@@ -124,7 +127,7 @@
   {
     path p; PathReserve(p, Size + 1);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       path& pref = p.assign(TestPath, TestPathEnd);
       assert(&pref == &p);
     }
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.concat.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.concat.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.concat.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.concat.pass.cpp
@@ -36,6 +36,9 @@
 #include <string_view>
 #include <cassert>
 
+// On Windows, charset conversions cause allocations in the path class in
+// cases where no allocations are done on other platforms.
+
 #include "test_macros.h"
 #include "test_iterators.h"
 #include "count_new.h"
@@ -98,7 +101,7 @@
     path LHS(L); PathReserve(LHS, ReserveSize);
     Str  RHS(R);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       LHS += RHS;
     }
     assert(LHS == E);
@@ -108,7 +111,7 @@
     path LHS(L); PathReserve(LHS, ReserveSize);
     StrView  RHS(R);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       LHS += RHS;
     }
     assert(LHS == E);
@@ -118,7 +121,7 @@
     path LHS(L); PathReserve(LHS, ReserveSize);
     Ptr RHS(R);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       LHS += RHS;
     }
     assert(LHS == E);
@@ -127,7 +130,7 @@
     path LHS(L); PathReserve(LHS, ReserveSize);
     Ptr RHS(R);
     {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       LHS.concat(RHS, StrEnd(RHS));
     }
     assert(LHS == E);
@@ -135,9 +138,9 @@
   // input iterator - For non-native char types, appends needs to copy the
   // iterator range into a contiguous block of memory before it can perform the
   // code_cvt conversions.
-  // For "char" no allocations will be performed because no conversion is
-  // required.
-  bool DisableAllocations = std::is_same<CharT, char>::value;
+  // For the path native type, no allocations will be performed because no
+  // conversion is required.
+  bool DisableAllocations = std::is_same<CharT, path::value_type>::value;
   {
     path LHS(L); PathReserve(LHS, ReserveSize);
     InputIter RHS(R);
@@ -367,7 +370,7 @@
     }
     {
       path LHS((const char*)TC.lhs);
-      std::string_view RHS((const char*)TC.rhs);
+      std::basic_string_view<path::value_type> RHS((const path::value_type*)TC.rhs);
       const char* E = TC.expect;
       PathReserve(LHS, StrLen(E) + 5);
       {
diff --git a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/string_alloc.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/string_alloc.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/string_alloc.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/path.member/path.native.obs/string_alloc.pass.cpp
@@ -25,6 +25,10 @@
 #include <type_traits>
 #include <cassert>
 
+// On Windows, charset conversions cause allocations in the path class in
+// cases where no allocations are done on other platforms, as long as
+// CharT isn't the path native type (wchar_t).
+
 #include "test_macros.h"
 #include "test_iterators.h"
 #include "count_new.h"
@@ -45,7 +49,7 @@
   Ptr value = MS;
   const path p((const char*)MS);
   {
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       Str s = p.string<CharT>();
       assert(s == value);
       Str s2 = p.string<CharT>(Alloc{});
@@ -56,7 +60,7 @@
   {
       using Traits = std::char_traits<CharT>;
       using AStr = std::basic_string<CharT, Traits, MAlloc>;
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       AStr s = p.string<CharT, Traits, MAlloc>();
       assert(s == value);
       assert(MAlloc::alloc_count == 0);
@@ -66,7 +70,7 @@
   { // Other allocator - provided copy
       using Traits = std::char_traits<CharT>;
       using AStr = std::basic_string<CharT, Traits, MAlloc>;
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       MAlloc a;
       // don't allow another allocator to be default constructed.
       MAlloc::disable_default_constructor = true;
@@ -97,7 +101,7 @@
   { // Other allocator - default construct
       using Traits = std::char_traits<CharT>;
       using AStr = std::basic_string<CharT, Traits, MAlloc>;
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       AStr s = p.string<CharT, Traits, MAlloc>();
       assert(s == value);
       assert(MAlloc::alloc_count > 0);
@@ -107,7 +111,7 @@
   { // Other allocator - provided copy
       using Traits = std::char_traits<CharT>;
       using AStr = std::basic_string<CharT, Traits, MAlloc>;
-      DisableAllocationGuard g;
+      NOT_WIN(DisableAllocationGuard g);
       MAlloc a;
       // don't allow another allocator to be default constructed.
       MAlloc::disable_default_constructor = true;
diff --git a/libcxx/test/support/test_macros.h b/libcxx/test/support/test_macros.h
--- a/libcxx/test/support/test_macros.h
+++ b/libcxx/test/support/test_macros.h
@@ -371,6 +371,12 @@
 #define TEST_NOINLINE
 #endif
 
+#ifdef _WIN32
+#define NOT_WIN(...) ((void)0)
+#else
+#define NOT_WIN(...) __VA_ARGS__
+#endif
+
 #if defined(__GNUC__)
 #pragma GCC diagnostic pop
 #endif