diff --git a/mcp/src/test/java/io/modelcontextprotocol/client/StdioMcpAsyncClientTests.java b/mcp/src/test/java/io/modelcontextprotocol/client/StdioMcpAsyncClientTests.java
index 95230942c..c39080138 100644
--- a/mcp/src/test/java/io/modelcontextprotocol/client/StdioMcpAsyncClientTests.java
+++ b/mcp/src/test/java/io/modelcontextprotocol/client/StdioMcpAsyncClientTests.java
@@ -22,9 +22,17 @@ class StdioMcpAsyncClientTests extends AbstractMcpAsyncClientTests {
 
 	@Override
 	protected McpClientTransport createMcpTransport() {
-		ServerParameters stdioParams = ServerParameters.builder("npx")
-			.args("-y", "@modelcontextprotocol/server-everything", "dir")
-			.build();
+		ServerParameters stdioParams;
+		if (System.getProperty("os.name").toLowerCase().contains("win")) {
+			stdioParams = ServerParameters.builder("cmd.exe")
+				.args("/c", "npx.cmd", "-y", "@modelcontextprotocol/server-everything", "dir")
+				.build();
+		}
+		else {
+			stdioParams = ServerParameters.builder("npx")
+				.args("-y", "@modelcontextprotocol/server-everything", "dir")
+				.build();
+		}
 		return new StdioClientTransport(stdioParams);
 	}
 
diff --git a/mcp/src/test/java/io/modelcontextprotocol/client/StdioMcpSyncClientTests.java b/mcp/src/test/java/io/modelcontextprotocol/client/StdioMcpSyncClientTests.java
index 925852b5b..8e75c4a3d 100644
--- a/mcp/src/test/java/io/modelcontextprotocol/client/StdioMcpSyncClientTests.java
+++ b/mcp/src/test/java/io/modelcontextprotocol/client/StdioMcpSyncClientTests.java
@@ -30,10 +30,17 @@ class StdioMcpSyncClientTests extends AbstractMcpSyncClientTests {
 
 	@Override
 	protected McpClientTransport createMcpTransport() {
-		ServerParameters stdioParams = ServerParameters.builder("npx")
-			.args("-y", "@modelcontextprotocol/server-everything", "dir")
-			.build();
-
+		ServerParameters stdioParams;
+		if (System.getProperty("os.name").toLowerCase().contains("win")) {
+			stdioParams = ServerParameters.builder("cmd.exe")
+				.args("/c", "npx.cmd", "-y", "@modelcontextprotocol/server-everything", "dir")
+				.build();
+		}
+		else {
+			stdioParams = ServerParameters.builder("npx")
+				.args("-y", "@modelcontextprotocol/server-everything", "dir")
+				.build();
+		}
 		return new StdioClientTransport(stdioParams);
 	}