diff --git a/action.yml b/action.yml
index ab731d8..12d5235 100644
--- a/action.yml
+++ b/action.yml
@@ -20,6 +20,10 @@ inputs:
     description: 'Set default Open Watcom environment variables (WATCOM + INCLUDE + PATH)'
     required: false
     default: true
+  target:
+    description: 'Set target OS specific Open Watcom header search path (INCLUDE)'
+    required: false
+    default: ''
 runs:
   using: 'node20'
   main: 'index.js'
diff --git a/src/main.ts b/src/main.ts
index 5ce39a5..4e8e978 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -9,6 +9,8 @@ import * as exec from "@actions/exec";
 function getInputs(): ISetupWatcomSettings {
   const p_version = core.getInput("version");
   const version_allowed = ["1.8", "1.9", "2.0", "2.0-64"];
+  const p_target = core.getInput("target");
+  const target_allowed = ["", "dos", "win", "nt", "os2", "os2-16", "linux"];
 
   if (!version_allowed.includes(p_version.toLowerCase())) {
     throw new Error(
@@ -18,6 +20,14 @@ function getInputs(): ISetupWatcomSettings {
     );
   }
 
+  if (!target_allowed.includes(p_target.toLowerCase())) {
+    throw new Error(
+      `"target" needs to be one of ${target_allowed.join(
+        ", ",
+      )}, got ${p_target}`,
+    );
+  }
+
   let p_url: string;
   let p_needs_chmod = false;
   let p_archive_type: ArchiveType;
@@ -58,7 +68,6 @@ function getInputs(): ISetupWatcomSettings {
     } else {
       p_path_subdir = "BINNT";
     }
-    p_inc_subdirs = ["H", "H\\NT", "H\\NT\\DIRECTX", "H\\NT\\DDK"];
   } else if (process.platform === "darwin") {
     if (p_version !== "2.0-64") {
       throw new Error("Unsupported platform");
@@ -70,15 +79,57 @@ function getInputs(): ISetupWatcomSettings {
     } else {
       throw new Error("Unsupported platform");
     }
-    p_inc_subdirs = ["lh"];
   } else {
     if (p_version == "2.0-64") {
       p_path_subdir = "binl64";
     } else {
       p_path_subdir = "binl";
     }
-    p_inc_subdirs = ["lh"];
   }
+  if (process.platform === "win32") {
+    switch (p_target) {
+    case "dos":
+      p_inc_subdirs = ["H"];
+      break;
+    case "win":
+      p_inc_subdirs = ["H", "H\\WIN"];
+      break;
+    case "os2":
+      p_inc_subdirs = ["H", "H\\OS2"];
+      break;
+    case "os2-16":
+      p_inc_subdirs = ["H", "H\\OS21X"];
+      break;
+    case "linux":
+      p_inc_subdirs = ["LH"];
+      break;
+    case "nt":
+    default:
+      p_inc_subdirs = ["H", "H\\NT", "H\\NT\\DIRECTX", "H\\NT\\DDK"];
+    }
+  } else {
+    switch (p_target) {
+    case "dos":
+      p_inc_subdirs = ["h"];
+      break;
+    case "win":
+      p_inc_subdirs = ["h", "h/win"];
+      break;
+    case "nt":
+      p_inc_subdirs = ["h", "h/nt", "h/nt/directx", "h/nt/ddk"];
+      break;
+    case "os2":
+      p_inc_subdirs = ["h", "h/os2"];
+      break;
+    case "os2-16":
+      p_inc_subdirs = ["h", "h/os21x"];
+      break;
+    case "linux":
+    default:
+      p_inc_subdirs = ["lh"];
+    }
+  }
+
   let p_location = core.getInput("location");
   if (!p_location) {
     if (process.platform === "win32") {