diff --git a/setup.py b/setup.py
index 5c9241de08..fe32355ef0 100644
--- a/setup.py
+++ b/setup.py
@@ -116,7 +116,7 @@ def is_pip():
 class CMakeExtension(Extension):
     def __init__(self, name, sourcedir=""):
         Extension.__init__(self, name, sources=[])
-        self.sourcedir = os.path.abspath(sourcedir)
+        self.sourcedir = os.path.abspath(sourcedir).replace('\\','/')
 
 
 class CMakeBuild(build_ext):
@@ -177,8 +177,8 @@ def build_extension(self, ext):
             )
 
         cmake_args = [
-            "-DCMAKE_LIBRARY_OUTPUT_DIRECTORY=" + extdir,
-            "-DPYTHON_EXECUTABLE=" + sys.executable,
+            "-DCMAKE_LIBRARY_OUTPUT_DIRECTORY=" + extdir.replace('\\','/'),
+            "-DPYTHON_EXECUTABLE=" + sys.executable.replace('\\','/'),
             "-DCMAKE_EXPORT_COMPILE_COMMANDS={}".format("OFF" if is_pip() else "ON"),
         ]
         cmake_args += shlex.split(args.cmake_args)
@@ -196,8 +196,9 @@ def build_extension(self, ext):
         # doesn't require a number (but builds sequentially by default), so we
         # add the argument only when it's not ninja or the number of jobs is
         # specified.
-        if not has_ninja() or self.parallel:
-            build_args += ["-j{}".format(self.parallel) if self.parallel else "-j"]
+        if sys.platform != "win32":
+            if not has_ninja() or self.parallel:
+                build_args += ["-j{}".format(self.parallel) if self.parallel else "-j"]
 
         cmake_args += [
             "-DBUILD_GUI_VIEWERS={}".format("ON" if not args.headless else "OFF")
@@ -211,13 +212,13 @@ def build_extension(self, ext):
 
         if self.run_cmake(cmake_args):
             subprocess.check_call(
-                shlex.split("cmake -H{} -B{}".format(ext.sourcedir, self.build_temp))
+                shlex.split("cmake -H{} -B{}".format(ext.sourcedir, self.build_temp.replace('\\','/')))
                 + cmake_args,
                 env=env,
             )
 
         subprocess.check_call(
-            shlex.split("cmake --build {}".format(self.build_temp)) + build_args
+            shlex.split("cmake --build {}".format(self.build_temp.replace('\\','/'))) + build_args
         )
         print()  # Add an empty line for cleaner output
 
@@ -226,7 +227,7 @@ def build_extension(self, ext):
             return
 
         if not args.headless:
-            link_dst = osp.join(self.build_temp, "viewer")
+            link_dst = osp.join(self.build_temp, "viewer").replace('\\','/')
             if not osp.islink(link_dst):
                 os.symlink(
                     osp.abspath(osp.join(self.build_temp, "utils/viewer/viewer")),
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b69e2dff0b..3d8e2bb280 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -7,7 +7,7 @@ cmake_minimum_required(VERSION 3.10)
 project(esp)
 
 if(MSVC)
-  add_definitions(/DNOMINMAX)
+  add_definitions(/DNOMINMAX  /D_USE_MATH_DEFINES /DEIGEN_DONT_ALIGN_STATICALLY)
 endif()
 
 find_program(CCACHE_FOUND ccache)
diff --git a/src/esp/assets/FRLInstanceMeshData.cpp b/src/esp/assets/FRLInstanceMeshData.cpp
index ceb8bfb4bb..0a310d7e4b 100644
--- a/src/esp/assets/FRLInstanceMeshData.cpp
+++ b/src/esp/assets/FRLInstanceMeshData.cpp
@@ -18,8 +18,7 @@
 #include <vector>
 
 #include <fcntl.h>
-#include <sys/mman.h>
-#include <unistd.h>
+
 #include <fstream>
 #include <sstream>
 #include <unordered_map>
diff --git a/src/esp/assets/GenericInstanceMeshData.cpp b/src/esp/assets/GenericInstanceMeshData.cpp
index 2ca79b1ed9..90fc5bbe43 100644
--- a/src/esp/assets/GenericInstanceMeshData.cpp
+++ b/src/esp/assets/GenericInstanceMeshData.cpp
@@ -18,8 +18,6 @@
 #include <vector>
 
 #include <fcntl.h>
-#include <sys/mman.h>
-#include <unistd.h>
 #include <fstream>
 #include <sstream>
 #include <unordered_map>
diff --git a/src/esp/assets/PTexMeshData.cpp b/src/esp/assets/PTexMeshData.cpp
index 1fe9989c94..4fbbfec94b 100644
--- a/src/esp/assets/PTexMeshData.cpp
+++ b/src/esp/assets/PTexMeshData.cpp
@@ -5,8 +5,59 @@
 #include "PTexMeshData.h"
 
 #include <fcntl.h>
+#ifndef _WIN32
 #include <sys/mman.h>
 #include <unistd.h>
+#else
+#include <io.h> 
+#include <Windows.h>
+
+#define PROT_READ 1
+#define MAP_PRIVATE 4
+
+// Note: This is not a full implementation of mmap/munmap.  It is is only meant to work in limited scenarios
+void* mmap(void* addr, size_t length, int prot, int flags, int fd, off_t off) {
+
+  ASSERT(prot == PROT_READ && flags == MAP_PRIVATE);
+
+  DWORD newProt = PAGE_READONLY;
+
+  void* ret;
+
+  HANDLE h = INVALID_HANDLE_VALUE;
+  h = (HANDLE)_get_osfhandle(fd);
+
+  HANDLE fmh = CreateFileMapping(
+    h,
+    nullptr,
+    newProt | SEC_COMMIT | SEC_RESERVE,
+    (DWORD)((length >> 32) & 0xFFFFFFFF),
+    (DWORD)(length & 0xFFFFFFFF),
+    nullptr);
+  ret = MapViewOfFileEx(
+    fmh,
+    FILE_MAP_ALL_ACCESS,
+    (DWORD)((off >> 32) & 0xFFFFFFFF),
+    (DWORD)(off & 0xFFFFFFFF),
+    0,
+    addr);
+  if (ret == nullptr) {
+    ret = NULL;
+  }
+  CloseHandle(fmh);
+
+  return ret;
+}
+
+int munmap(void* addr, size_t length) {
+  // Try to unmap it as a file.
+  if (!UnmapViewOfFile(addr)) {
+    return -1;
+  }
+  return 0;
+}
+#endif
+
 #include <fstream>
 #include <sstream>
 #include <unordered_map>
@@ -93,7 +144,7 @@ std::vector<PTexMeshData::MeshData> splitMesh(
 
 // calculate vertex grid position and code
 #pragma omp parallel for
-  for (size_t i = 0; i < mesh.vbo.size(); i++) {
+  for (int32_t i = 0; i < mesh.vbo.size(); i++) {
     const vec3f p = mesh.vbo[i].head<3>();
     vec3f pi = (p - boundingBox.min()) / splitSize;
     verts[i] = EncodeMorton3(pi.cast<int>());
@@ -112,7 +163,7 @@ std::vector<PTexMeshData::MeshData> splitMesh(
   faces.resize(numFaces);
 
 #pragma omp parallel for
-  for (size_t i = 0; i < numFaces; i++) {
+  for (int32_t i = 0; i < numFaces; i++) {
     faces[i].originalFace = i;
     faces[i].code = std::numeric_limits<uint32_t>::max();
     for (int j = 0; j < 4; j++) {
@@ -158,7 +209,7 @@ std::vector<PTexMeshData::MeshData> splitMesh(
   }
 
 #pragma omp parallel for
-  for (size_t i = 0; i < numChunks; i++) {
+  for (int32_t i = 0; i < numChunks; i++) {
     uint32_t chunkSize = chunkStart[i + 1] - chunkStart[i];
 
     std::vector<uint32_t> refdVerts;
diff --git a/src/esp/gfx/PTexMeshShader.cpp b/src/esp/gfx/PTexMeshShader.cpp
index 68153ecfac..243e97e536 100644
--- a/src/esp/gfx/PTexMeshShader.cpp
+++ b/src/esp/gfx/PTexMeshShader.cpp
@@ -5,7 +5,6 @@
 #include "PTexMeshShader.h"
 
 #include <fcntl.h>
-#include <sys/mman.h>
 #include <iostream>
 
 #include <Corrade/Containers/Reference.h>
diff --git a/src/esp/gfx/WindowlessContext.cpp b/src/esp/gfx/WindowlessContext.cpp
index a1c8c8225c..e8a896f671 100644
--- a/src/esp/gfx/WindowlessContext.cpp
+++ b/src/esp/gfx/WindowlessContext.cpp
@@ -18,7 +18,7 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <unistd.h>
-#elif __win32__
+#elif __win32__ || defined(_WIN32)
 #include <Magnum/Platform/WindowlessWglApplication.h>
 #endif
 
diff --git a/src/esp/nav/PathFinder.h b/src/esp/nav/PathFinder.h
index 78729084e2..ad4b59dc23 100644
--- a/src/esp/nav/PathFinder.h
+++ b/src/esp/nav/PathFinder.h
@@ -18,7 +18,7 @@ class dtQueryPathState;
 namespace esp {
 // forward declaration
 namespace assets {
-class MeshData;
+struct MeshData;
 }
 namespace nav {