diff --git a/scripts/build_runtime.py b/scripts/build_runtime.py
index 7dc98b0..3826b25 100644
--- a/scripts/build_runtime.py
+++ b/scripts/build_runtime.py
@@ -217,13 +217,19 @@ def build_wasm3_lib_win(release):
 
 
 def build_wasm3_lib_mac(release):
+    includes = ["-I./ext/wasm3/source"]
+    debug_flags = ["-O2"] if release else ["-g"]
+    flags = [
+        *debug_flags,
+        "-foptimize-sibling-calls",
+        "-Wno-extern-initializer",
+        "-Dd_m3VerboseErrorMessages",
+    ]
+
     for f in glob.iglob("./ext/wasm3/source/*.c"):
         name = os.path.splitext(os.path.basename(f))[0] + ".o"
         subprocess.run([
-            "clang", "-c",
-            "-g", *(["/O2"] if release else []),
-            "-foptimize-sibling-calls", "-Wno-extern-initializer", "-Dd_m3VerboseErrorMessages",
-            "-I./ext/wasm3/source",
+            "clang", "-c", *flags, *includes,
             "-o", f"./bin/obj/{name}",
             f,
         ], check=True)
@@ -239,8 +245,7 @@ def build_orca(release):
     if platform.system() == "Windows":
         build_orca_win(release)
     elif platform.system() == "Darwin":
-        log_error("can't yet build Orca on Mac")
-        exit(1)
+        build_orca_mac(release)
     else:
         log_error(f"can't build Orca for unknown platform '{platform.system()}'")
         exit(1)
@@ -254,23 +259,7 @@ def build_orca_win(release):
     shutil.copy("milepost\\bin\\milepost.dll.lib", "bin")
     shutil.copy(os.path.join(pthread_dir, "bin\\pthreadVC3.dll"), "bin")
 
-    # generate wasm3 api bindings
-    bindgen("core", "src")
-    bindgen("gles", "src")
-    bindgen2("canvas", "src\\canvas_api.json",
-        guest_stubs="sdk\\orca_surface.c",
-        guest_include="graphics.h",
-        wasm3_bindings="src\\canvas_api_bind_gen.c",
-    )
-    bindgen2("clock", "src\\clock_api.json",
-        guest_stubs="sdk\\orca_clock.c",
-        guest_include="platform_clock.h",
-        wasm3_bindings="src\\clock_api_bind_gen.c",
-    )
-    bindgen2("io", "src\\io_api.json",
-        guest_stubs="sdk\\io_stubs.c",
-        wasm3_bindings="src\\io_api_bind_gen.c",
-    )
+    gen_all_bindings()
 
     # compile orca
     pthread_include = os.path.join(pthread_dir, "include")
@@ -301,6 +290,70 @@ def build_orca_win(release):
     ], check=True)
 
 
+def build_orca_mac(release):
+    # copy libraries
+    shutil.copy("milepost/bin/mtl_renderer.metallib", "bin/")
+    shutil.copy("milepost/bin/libmilepost.dylib", "bin/")
+    shutil.copy("milepost/bin/libGLESv2.dylib", "bin/")
+    shutil.copy("milepost/bin/libEGL.dylib", "bin/")
+
+    includes = [
+        "-Isrc",
+        "-Isdk",
+        "-Imilepost/src",
+        "-Imilepost/src/util",
+        "-Imilepost/src/platform",
+        "-Iext/wasm3/source",
+        "-Imilepost/ext/",
+    ]
+    libs = ["-Lbin", "-lmilepost", "-lwasm3"]
+    debug_flags = ["-O2"] if release else ["-g", "-DLOG_COMPILE_DEBUG"]
+    flags = [
+        *debug_flags,
+        "-mmacos-version-min=10.15.4",
+        "-maes",
+    ]
+
+    gen_all_bindings()
+
+    # compile orca
+    subprocess.run([
+        "clang", *flags, *includes, *libs,
+        "-o", "bin/orca",
+        "src/main.c",
+    ], check=True)
+
+    # fix libs imports
+    subprocess.run([
+        "install_name_tool", "-change",
+        "./bin/libmilepost.dylib", "@rpath/libmilepost.dylib", "bin/orca",
+    ], check=True)
+    subprocess.run([
+        "install_name_tool", "-add_rpath",
+        "@executable_path/", "bin/orca",
+    ], check=True)
+
+
+def gen_all_bindings():
+    bindgen("core", "src")
+    bindgen("gles", "src")
+
+    bindgen2("canvas", "src/canvas_api.json",
+        guest_stubs="sdk/orca_surface.c",
+        guest_include="graphics.h",
+        wasm3_bindings="src/canvas_api_bind_gen.c",
+    )
+    bindgen2("clock", "src/clock_api.json",
+        guest_stubs="sdk/orca_clock.c",
+        guest_include="platform_clock.h",
+        wasm3_bindings="src/clock_api_bind_gen.c",
+    )
+    bindgen2("io", "src/io_api.json",
+        guest_stubs="sdk/io_stubs.c",
+        wasm3_bindings="src/io_api_bind_gen.c",
+    )
+
+
 def ensure_programs():
     if platform.system() == "Windows":
         try: