diff --git a/lib/plug/conn/query.ex b/lib/plug/conn/query.ex
index 06db79b4..8d7764c3 100644
--- a/lib/plug/conn/query.ex
+++ b/lib/plug/conn/query.ex
@@ -80,7 +80,7 @@ defmodule Plug.Conn.Query do
   `invalid_exception` is the exception module for the exception to raise on
   errors with decoding.
   """
-  @spec decode(String.t(), map(), module(), boolean()) :: %{optional(String.t()) => term()}
+  @spec decode(String.t(), keyword(), module(), boolean()) :: %{optional(String.t()) => term()}
   def decode(
         query,
         initial \\ [],