diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+## 2.3.5
+
+* Adds `addToRequestQueryString` helper function
+
 ## 2.3.4
 
 * Reexport RequestHeaders from Network.HTTP.Types (what was intended in last version)
diff --git a/Network/HTTP/Simple.hs b/Network/HTTP/Simple.hs
--- a/Network/HTTP/Simple.hs
+++ b/Network/HTTP/Simple.hs
@@ -57,6 +57,7 @@
     , setRequestHeaders
     , setRequestQueryString
     , getRequestQueryString
+    , addToRequestQueryString
       -- ** Request body
     , setRequestBody
     , setRequestBodyJSON
@@ -346,6 +347,13 @@
 -- @since 2.1.10
 setRequestQueryString :: H.Query -> H.Request -> H.Request
 setRequestQueryString = H.setQueryString
+
+-- | Add to the existing query string parameters.
+--
+-- @since 2.3.5
+addToRequestQueryString :: H.Query -> H.Request -> H.Request
+addToRequestQueryString additions req = setRequestQueryString q req
+    where q = additions <> getRequestQueryString req
 
 -- | Set the request body to the given 'H.RequestBody'. You may want to
 -- consider using one of the convenience functions in the modules, e.g.
diff --git a/http-conduit.cabal b/http-conduit.cabal
--- a/http-conduit.cabal
+++ b/http-conduit.cabal
@@ -1,5 +1,5 @@
 name:            http-conduit
-version:         2.3.4
+version:         2.3.5
 license:         BSD3
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>
@@ -29,7 +29,7 @@
                  , conduit               >= 1.2
                  , conduit-extra         >= 1.1
                  , http-types            >= 0.7
-                 , http-client           >= 0.5.13  && < 0.6
+                 , http-client           >= 0.5.13  && < 0.7
                  , http-client-tls       >= 0.3     && < 0.4
                  , mtl
                  , unliftio-core