diff --git a/build.py b/build.py
index 359d093..67ed216 100755
--- a/build.py
+++ b/build.py
@@ -7,10 +7,6 @@ import os
 import sys
 import pyjson5
 
-dependencies = [
-    'nasm',
-    'llvm-ar'
-]
 
 # Parse command line arguments
 arg_parser = argparse.ArgumentParser('build.py')
@@ -23,17 +19,25 @@ arg_parser.add_argument('--cflags', nargs='*', default=[], help='Pass additional
 args = arg_parser.parse_args()
 compiler = args.compiler
 
-print('==> Performing basic checks')
 
 # Perform cleaning if required
+def rm(path):
+    if os.path.exists(path):
+        os.remove(path)
 if args.clean:
-    shutil.rmtree('bin')
-    shutil.rmtree('lib')
-    os.remove(os.path.join('src', 'ciabatta.c'))
-    os.remove('a')
+    if os.path.exists('bin'):
+        shutil.rmtree('bin')
+    if os.path.exists('lib'):
+        shutil.rmtree('lib')
+    rm(os.path.join('src', 'ciabatta.c'))
+    rm('a')
+    rm('a.exe')
+    rm('a.ilk')
+    rm('a.pdb')
     sys.exit(0)
 
 # Check host OS
+print('==> Performing basic checks')
 target = args.target
 if target is None:
     host_os = platform.system().lower()
@@ -44,8 +48,31 @@ if target is None:
     target = host_os
 
 # Add compiler to dependencies
+dependencies = [
+    'nasm',
+    'llvm-ar'
+]
 dependencies.append(args.compiler)
 
+
+# Figure out the flags
+includes = ['include']
+cc = args.compiler
+cc_defines = []
+cc_flags = ['-nostdlib']
+crt_file = 'crt.lib'
+lib_file = 'cia.lib'
+if args.mode == 'release':
+    cc_flags.append('-O2')
+    cc_defines.append('NDEBUG')
+else: # 'debug'
+    cc_flags.append('-g')
+    cc_flags.append('-O0')
+    cc_defines.append('DEBUG')
+if target != 'windows':
+    cc_flags.append('-fpic')
+cc_defines.append(f'_CIA_OS_{target.upper()}')
+
 # Check dependencies
 print('==> Checking dependencies')
 for dependency in dependencies:
@@ -54,24 +81,6 @@ for dependency in dependencies:
         sys.exit(1)
 print('  -> Everything OK')
 
-# Figure out the flags
-includes = ['include']
-cc = ''
-cc_defines = []
-cc_flags = ['-nostdlib']
-crt_file = 'crt.lib'
-lib_file = 'cia.lib'
-
-cc = args.compiler
-if args.mode == 'release':
-    cc_flags.append('-O2')
-    cc_defines.append('NDEBUG')
-else: # 'debug'
-    cc_flags.append('-g')
-    cc_flags.append('-O0')
-    cc_defines.append('DEBUG')
-cc_defines.append(f'_CIA_OS_{target.upper()}')
-
 # Generate TinyRT headers for the target platform
 print(f"==> Generating TinyRT header for {target}")
 tinyrt_config_path = os.path.join('src', target, 'tinyrt.json')
@@ -133,8 +142,8 @@ try:
         if platform_config is None:
             print(f"  -> [ERROR] library config doesn't contain configuration for platform {target}")
         for include in platform_config['includes']:
-            include_path = os.path.join(platform_config['path'], include)
-            ciabatta_header.write(f'#include "{include_path}"\n')
+            include_path = platform_config['path']
+            ciabatta_header.write(f'#include "{include_path}/{include}"\n')
         ciabatta_header.write(f'#include "{target}/tinyrt-iface.h"\n')
         ciabatta_header.write(f'#include <tinyrt.h>\n')
         for tinyrt_source in platform_config['tinyrt']:
@@ -193,7 +202,7 @@ def assemble(src, out):
 def compile(srcs, out, extra_flags = ''):
     flags = cc_flags_str + ' ' + extra_flags + ' '.join(args.cflags)
     inputs = ' '.join(map(quote, srcs))
-    cmdline = f'{compiler} {flags} {inputs} -o {quote(out)}'
+    cmdline = f'{cc} {flags} {inputs} -o {quote(out)}'
     print('  >', cmdline)
     code = os.system(cmdline)
     if code != 0:
@@ -207,20 +216,34 @@ def archive(srcs, out):
     if code != 0:
         sys.exit(code)
 
-
 # Ciabatta build spec
 if not os.path.exists('lib'):
     os.mkdir('lib')
 if not os.path.exists('bin'):
     os.mkdir('bin')
 
-p = os.path.join
+def p(path):
+    l = path.split('/')
+    return os.path.join(*l)
 
-assemble(p('src', 'linux', 'crt-entry.asm'), p('bin', 'crt-entry.o'))
-compile([p('src', 'linux', 'crt-ctors.c')], p('bin', 'crt-ctors.o'), '-fpic -c')
-compile([p('src', 'ciabatta.c')], p('bin', 'ciabatta.o'), '-fpic -c')
-archive([p('bin', 'crt-ctors.o'), p('bin', 'crt-entry.o')], p('lib', crt_file))
-archive([p('bin', 'ciabatta.o'), ], p('lib', lib_file))
+cia_lib = p(f'lib/{lib_file}')
+crt_lib = p(f'lib/{crt_file}')
+ciabatta_c = p('src/ciabatta.c')
+ciabatta_o = p('bin/ciabatta.o')
+
+if target == 'linux':
+    assemble(p('src/linux/crt-entry.asm'), p('bin/crt-entry.o'))
+    compile([p('src/linux/crt-ctors.c')], p('bin/crt-ctors.o'), '-c')
+    archive([p('bin/crt-ctors.o'), p('bin/crt-entry.o')], p('lib', crt_file))
+elif target == 'windows':
+    assemble(p('src/windows/chkstk.asm'), p('bin/chkstk.o'))
+    compile([p('src/windows/crt-entry.c')], p('bin/crt-entry.o'), '-c')
+    archive([p('bin/crt-entry.o')], crt_lib)
+compile([ciabatta_c], ciabatta_o, '-c')
+archive([ciabatta_o], cia_lib)
 
 if args.test:
-    compile([args.test, p('lib', lib_file), p('lib', crt_file)], 'a', '-pie')
+    if target == 'linux':
+        compile([args.test, cia_lib, crt_lib], 'a', '-pie')
+    elif target == 'windows':
+        compile([args.test, cia_lib, crt_lib], 'a.exe', '-lkernel32')
diff --git a/include/cia-def.h b/include/cia-def.h
index a4d2be9..0f81d92 100644
--- a/include/cia-def.h
+++ b/include/cia-def.h
@@ -1,9 +1,16 @@
 
 #pragma once
 
+// Since we're re-defining noreturn below, this would mess
+// with __declspec(noreturn) in windows headers, which
+// is hidden behind a define. Good thing, because now we
+// can override that define over here.
+#if defined(_CIA_OS_WINDOWS)
+    #define DECLSPEC_NORETURN __declspec("noreturn")
+#endif
+
 // Pre-C23 keyword macros and stddef
 #define static_assert _Static_assert
-#define noreturn _Noreturn
 #define NULL ((void *)0)
 
 // Assert commonly-accepted platform-invariant sizes
diff --git a/include/stdlib.h b/include/stdlib.h
index a0a5ac5..97e1ac3 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -5,7 +5,7 @@
 
 int atexit(void (*func)(void));
 int at_quick_exit(void (*func)(void));
-noreturn void abort(void);
-noreturn void exit(int code);
-noreturn void _Exit(int code);
-noreturn void quick_exit(int code);
\ No newline at end of file
+[[noreturn]] void abort(void);
+[[noreturn]] void exit(int code);
+[[noreturn]] void _Exit(int code);
+[[noreturn]] void quick_exit(int code);
\ No newline at end of file
diff --git a/include/tinyrt.h b/include/tinyrt.h
index 6099e32..5f22601 100644
--- a/include/tinyrt.h
+++ b/include/tinyrt.h
@@ -41,7 +41,7 @@ static _RT_Status _rt_deinit();
 
 // Program API
 #if _RT_API_PROGRAM == 1
-    static noreturn void _rt_program_exit(int code);
+    [[noreturn]] static void _rt_program_exit(int code);
 #endif
 
 #if _RT_API_ENVIRONMENT == 1
diff --git a/src/impl/stdlib-program/program.c b/src/impl/stdlib-program/program.c
index 97aa470..8bfe326 100644
--- a/src/impl/stdlib-program/program.c
+++ b/src/impl/stdlib-program/program.c
@@ -25,12 +25,13 @@ int at_quick_exit(void (*func)(void)) {
     return 0;
 }
 
-noreturn void abort(void) {
+[[noreturn]] void abort(void) {
     // TODO: Ideally do a debug trap if the process is being debugged
-    _Exit(-1);
+    _rt_program_exit(1);
+    __builtin_unreachable();
 }
 
-noreturn void exit(int code) {
+[[noreturn]] void exit(int code) {
     for(u64 i = n_atexit_handlers-1; i-- != 0; ) {
         void (*handler)(void) = atexit_handlers[i];
         handler();
@@ -38,17 +39,20 @@ noreturn void exit(int code) {
     // TODO(bumbread): flush all the unflushed file streams
     // TODO(bumbread): close all file streams and delete temporary files
     _rt_program_exit(code);
+    __builtin_unreachable();
 }
 
-noreturn void _Exit(int code) {
+[[noreturn]] void _Exit(int code) {
     _rt_program_exit(code);
+    __builtin_unreachable();
 }
 
-noreturn void quick_exit(int code) {
+[[noreturn]] void quick_exit(int code) {
     for(u64 i = n_at_quick_exit_handlers-1; i-- != 0; ) {
         void (*handler)(void) = at_quick_exit_handlers[i];
         handler();
     }
     _rt_program_exit(code);
+    __builtin_unreachable();
 }
 
diff --git a/src/library.json b/src/library.json
index ac2fab8..6c459a8 100644
--- a/src/library.json
+++ b/src/library.json
@@ -44,8 +44,13 @@ platforms: [
     {
         name: "windows",
         path: "windows",
-        includes: [],
-        tinyrt: [],
+        includes: [
+            "windows.c"
+        ],
+        tinyrt: [
+            "tinyrt.c",
+            "cia-init.c"
+        ],
     },
 ],
 
diff --git a/src/linux/tinyrt.c b/src/linux/tinyrt.c
index ec0b7ca..9916061 100644
--- a/src/linux/tinyrt.c
+++ b/src/linux/tinyrt.c
@@ -1,9 +1,6 @@
 
 // See src/tinyrt.h file for the interface this file implements
 
-static _RT_File _rt_file_stdin;
-static _RT_File _rt_file_stderr;
-
 static _RT_Status _rt_file_std_handles_init() {
     _rt_file_stdin.fd = 0;
     _rt_file_stdin.flags = _RT_FILE_READ;
@@ -68,6 +65,6 @@ static _RT_Status _rt_file_close(_RT_File *file) {
     return _RT_STATUS_OK;
 }
 
-static noreturn void _rt_program_exit(int code) {
+[[noreturn]] static void _rt_program_exit(int code) {
     syscall_exit(code);
 }
diff --git a/src/windows/chkstk.asm b/src/windows/chkstk.asm
new file mode 100644
index 0000000..d3dfb6d
--- /dev/null
+++ b/src/windows/chkstk.asm
@@ -0,0 +1,26 @@
+bits 64
+
+segment .text
+global __chkstk
+__chkstk:
+    sub   rsp, 0x10
+    mov   [rsp], r10
+    mov   [rsp+0x8], r11
+    xor   r11, r11
+    lea   r10, [rsp+0x18]
+    sub   r10, rax
+    cmovb r10, r11
+    mov   r11, gs:[0x10]
+    cmp   r10, r11
+    jnb   .end
+    and   r10w, 0xf000
+.loop:
+    lea   r11, [r11-0x1000]
+    mov   byte [r11], 0x0
+    cmp   r10, r11
+    jnz   .loop
+.end:
+    mov   r10, [rsp]
+    mov   r11, [rsp+0x8]
+    add   rsp, 0x10
+    ret
\ No newline at end of file
diff --git a/src/windows/cia-init.c b/src/windows/cia-init.c
new file mode 100644
index 0000000..da0f549
--- /dev/null
+++ b/src/windows/cia-init.c
@@ -0,0 +1,6 @@
+
+static void _fileapi_init();
+
+void _cia_init() {
+    _fileapi_init();
+}
diff --git a/src/windows/crt-entry.c b/src/windows/crt-entry.c
new file mode 100644
index 0000000..a3ae248
--- /dev/null
+++ b/src/windows/crt-entry.c
@@ -0,0 +1,62 @@
+
+#include <cia-def.h>
+#include "windows.c"
+
+extern int main(int argc, char **argv, char **envp);
+extern void _cia_init();
+
+void mainCRTStartup() {
+    _cia_init();
+    __security_init_cookie();
+    main(0, NULL, NULL);
+    ExitProcess(0);
+}
+
+void wmainCRTStartup() {
+    ExitProcess(0);    
+}
+
+void _WinMainCRTStartup() {
+    ExitProcess(0);
+}
+
+void wWinMainCRTStartup() {
+    ExitProcess(0);
+}
+
+BOOL _DllMainCRTStartup(HINSTANCE instance, DWORD reason, void *_reserved) {
+    switch(reason) {
+        case DLL_PROCESS_ATTACH: {
+            // Initialize once for each new process.
+            // Return FALSE to fail DLL load.
+        } break;
+        case DLL_THREAD_ATTACH: {
+            // Do thread-specific initialization.
+        } break;
+        case DLL_THREAD_DETACH: {
+            // Do thread-specific cleanup.
+        } break;
+        case DLL_PROCESS_DETACH: {
+            // Perform any necessary cleanup.
+        } break;
+    }
+    return TRUE;
+}
+
+u64 __security_cookie;
+
+void __security_init_cookie() {
+    // They say it's a random number so I generated
+    // one using numbergenerator.org
+    __security_cookie = 0xb26e04cc62ba48aULL;
+}
+
+void __security_check_cookie(u64 retrieved) {
+    if(__security_cookie != retrieved) {
+        char buf[] = "Buffer overrun detected!\n";
+        HANDLE stdout = GetStdHandle(STD_OUTPUT_HANDLE);
+        WriteFile(stdout, buf, sizeof buf, NULL, NULL);
+        // TODO: abort-like behaviour here
+        ExitProcess(1);
+    }
+}
diff --git a/src/windows/tinyrt.c b/src/windows/tinyrt.c
new file mode 100644
index 0000000..adc7680
--- /dev/null
+++ b/src/windows/tinyrt.c
@@ -0,0 +1,76 @@
+
+// See src/tinyrt.h file for the interface this file implements
+
+static _RT_Status _rt_file_std_handles_init() {
+    _rt_file_stdin.handle = GetStdHandle(STD_INPUT_HANDLE);
+    _rt_file_stdin.flags = _RT_FILE_READ;
+    _rt_file_stdout.handle = GetStdHandle(STD_OUTPUT_HANDLE);
+    _rt_file_stdout.flags = _RT_FILE_WRITE;
+    _rt_file_stderr.handle = GetStdHandle(STD_ERROR_HANDLE);
+    _rt_file_stdout.flags = _RT_FILE_WRITE;
+    return _RT_STATUS_OK;
+}
+
+static _RT_Status _rt_file_open(_RT_File *file, char const *name, int _rt_flags) {
+    u32 access = 0;
+    if(_rt_flags & _RT_FILE_READ) access |= GENERIC_READ;
+    if(_rt_flags & _RT_FILE_WRITE) access |= GENERIC_WRITE;
+    u32 share = 0;
+    if((_rt_flags & _RT_FILE_READ) == 0) share |= FILE_SHARE_READ;
+    u32 creation = 0;
+    if(_rt_flags & _RT_FILE_TRUNCATE) {
+        creation = TRUNCATE_EXISTING;
+    }
+    else if(_rt_flags & _RT_FILE_CREATE) {
+        if(_rt_flags & _RT_FILE_EXCLUSIVE) creation = CREATE_ALWAYS;
+        else creation = CREATE_NEW;
+    }
+    else {
+        if(_rt_flags & _RT_FILE_EXCLUSIVE) creation = OPEN_ALWAYS;
+        else creation = OPEN_EXISTING;
+    }
+    HANDLE handle = CreateFileA(name, access, share, NULL, creation, FILE_ATTRIBUTE_NORMAL, NULL);
+    if(file == INVALID_HANDLE_VALUE) {
+        // ERROR_FILE_NOT_FOUND
+        // ERROR_PATH_NOT_FOUND
+        // ERROR_ACCESS_DENIED
+        // ERROR_NOT_ENOUGH_MEMORY
+        return _RT_STATUS_FILE_IO_ERROR;
+        
+    }
+    file->handle = handle;
+    file->flags = _rt_flags;
+    return _RT_STATUS_OK;
+}
+
+static _RT_Status _rt_file_read(u64 size, void *buffer, _RT_File *from, u64 *out_bytes_read) {
+    *out_bytes_read = 0;
+    BOOL ok = ReadFile(from->handle, buffer, size, (unsigned long *)out_bytes_read, NULL);
+    if(!ok) {
+        return _RT_STATUS_FILE_IO_ERROR;
+    }
+    return _RT_STATUS_OK;
+}
+
+static _RT_Status _rt_file_write(_RT_File *to, u64 size, void *buffer, u64 *out_bytes_written) {
+    *out_bytes_written = 0;
+    BOOL ok = WriteFile(to->handle, buffer, size, (unsigned long *)out_bytes_written, NULL);
+    if(!ok) {
+        return _RT_STATUS_FILE_IO_ERROR;
+    }
+    return _RT_STATUS_OK;
+}
+
+static _RT_Status _rt_file_close(_RT_File *file) {
+    BOOL ok = CloseHandle(file->handle);
+    if(!ok) {
+        return _RT_STATUS_FILE_BAD_FILE;
+    }
+    return _RT_STATUS_OK;
+}
+
+[[noreturn]] static void _rt_program_exit(int code) {
+    ExitProcess(code);
+    __builtin_unreachable();
+}
+
diff --git a/src/windows/tinyrt.json b/src/windows/tinyrt.json
new file mode 100644
index 0000000..f82eb3f
--- /dev/null
+++ b/src/windows/tinyrt.json
@@ -0,0 +1,12 @@
+{
+
+// This file contains TinyRT API subsets that are exported
+// for this operating system, one name per line. This file
+// is used in a build script to generate tinyrt_macro file
+// and to resolve higher-level API dependencies
+
+rt_api_file: true,
+rt_api_program: true,
+rt_api_shell: false,
+
+}
\ No newline at end of file
diff --git a/src/windows/tinyrt.mf b/src/windows/tinyrt.mf
deleted file mode 100644
index e69de29..0000000
diff --git a/src/windows/windows.c b/src/windows/windows.c
new file mode 100644
index 0000000..0517779
--- /dev/null
+++ b/src/windows/windows.c
@@ -0,0 +1,6 @@
+
+#define NOGDI
+#define NOUSER
+#define NOMINMAX
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
diff --git a/tests/empty.c b/tests/empty.c
index 3de02c0..3f4d186 100644
--- a/tests/empty.c
+++ b/tests/empty.c
@@ -1,9 +1,4 @@
-
-#include <cia-def.h>
-#include <stdio.h>
-
-int main(int argc, char **argv, char **envp) {
-    char string[] = "Hello, world!\n";
-    fwrite(string, 1, sizeof string-1, stdout);
-    return 0;
-}
+
+int main(int argc, char **argv) {
+    return 0;
+}
diff --git a/tests/hello.c b/tests/hello.c
new file mode 100644
index 0000000..3de02c0
--- /dev/null
+++ b/tests/hello.c
@@ -0,0 +1,9 @@
+
+#include <cia-def.h>
+#include <stdio.h>
+
+int main(int argc, char **argv, char **envp) {
+    char string[] = "Hello, world!\n";
+    fwrite(string, 1, sizeof string-1, stdout);
+    return 0;
+}