diff --git a/wrapper/Ada/README.md b/wrapper/Ada/README.md
index f1696f261..845dadfaa 100644
--- a/wrapper/Ada/README.md
+++ b/wrapper/Ada/README.md
@@ -73,6 +73,13 @@ cd obj/
 ./tls_client_main 127.0.0.1
 ```
 
+On Windows, build the executables with:
+```sh
+gprbuild -XOS=Windows default.gpr
+gprbuild -XOS=Windows client.gpr
+```
+
+
 ### GNAT FSF Compiler and GPRBuild manual installation
 In May 2022 AdaCore announced the end of the GNAT Community releases.
 Pre-built binaries for the GNAT FSF compiler and GPRBuild can be
diff --git a/wrapper/Ada/client.gpr b/wrapper/Ada/client.gpr
index 7590d49d7..cdbf3dedf 100644
--- a/wrapper/Ada/client.gpr
+++ b/wrapper/Ada/client.gpr
@@ -1,4 +1,8 @@
 project Client is
+   type OS_Kind is ("Windows", "Linux_Or_Mac");
+
+   OS : OS_Kind := external ("OS", "Linux_Or_Mac");
+
    for Languages use ("C", "Ada");
 
    for Source_Dirs use (".",
@@ -55,8 +59,16 @@ project Client is
    end Compiler;
 
    package Linker is
-      for Switches ("Ada") use
-         ("-lm");  --  To include the math library (used by WolfSSL).
+      case OS is
+         when "Windows" =>
+            for Switches ("Ada") use
+               ("-lm",         --  To include the math library (used by WolfSSL).
+                "-lcrypt32");  --  Needed on Windows.
+
+         when "Linux_Or_Mac" =>
+            for Switches ("Ada") use
+               ("-lm");  --  To include the math library (used by WolfSSL).
+      end case;
    end Linker;
 
    package Binder is
diff --git a/wrapper/Ada/default.gpr b/wrapper/Ada/default.gpr
index ac535cad8..bbd3b34f1 100644
--- a/wrapper/Ada/default.gpr
+++ b/wrapper/Ada/default.gpr
@@ -72,12 +72,12 @@ project Default is
 
    package Linker is
       case OS is
-         when Windows =>
+         when "Windows" =>
             for Switches ("Ada") use
                ("-lm",         --  To include the math library (used by WolfSSL).
                 "-lcrypt32");  --  Needed on Windows.
 
-         when Linux_Or_Mac =>
+         when "Linux_Or_Mac" =>
             for Switches ("Ada") use
                ("-lm");  --  To include the math library (used by WolfSSL).
       end case;