diff --git a/lib/mcp/client/http.rb b/lib/mcp/client/http.rb
index 8b135e3..b5ba8e9 100644
--- a/lib/mcp/client/http.rb
+++ b/lib/mcp/client/http.rb
@@ -106,6 +106,10 @@ def parse_response_body(response, method, params)
           parse_sse_response(response.body, method, params)
         elsif content_type&.include?("application/json")
           response.body
+        elsif response.status == 202
+          # Server accepted the request and will deliver the response via an SSE stream.
+          # https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#sending-messages-to-the-server
+          { "accepted" => true }
         else
           raise RequestHandlerError.new(
             "Unsupported Content-Type: #{content_type.inspect}. Expected application/json or text/event-stream.",
diff --git a/test/mcp/client/http_test.rb b/test/mcp/client/http_test.rb
index 89d3649..c21441b 100644
--- a/test/mcp/client/http_test.rb
+++ b/test/mcp/client/http_test.rb
@@ -369,6 +369,21 @@ def test_send_request_parses_sse_error_response
         assert_equal("Invalid request", response.dig("error", "message"))
       end
 
+      def test_send_request_returns_accepted_for_202_response
+        request = {
+          jsonrpc: "2.0",
+          method: "notifications/initialized",
+        }
+
+        stub_request(:post, url)
+          .with(body: request.to_json)
+          .to_return(status: 202, body: "")
+
+        response = client.send_request(request: request)
+
+        assert_equal({ "accepted" => true }, response)
+      end
+
       def test_send_request_raises_error_for_sse_without_response
         request = {
           jsonrpc: "2.0",