diff --git a/m4/boost.m4 b/m4/boost.m4
index 973c447b0fa50..c5de2b63a6769 100644
--- a/m4/boost.m4
+++ b/m4/boost.m4
@@ -622,13 +622,6 @@ BOOST_DEFUN([Bind],
 [BOOST_FIND_HEADER([boost/bind.hpp])])
 
 
-# BOOST_CAST()
-# ------------
-# Look for Boost.Cast
-BOOST_DEFUN([Cast],
-[BOOST_FIND_HEADER([boost/cast.hpp])])
-
-
 # BOOST_CHRONO([PREFERRED-RT-OPT], [ERROR_ON_UNUSABLE])
 # --------------
 # Look for Boost.Chrono.
@@ -796,15 +789,6 @@ LDFLAGS=$boost_context_save_LDFLAGS
 ])# BOOST_CONTEXT
 
 
-# BOOST_CONVERSION()
-# ------------------
-# Look for Boost.Conversion (cast / lexical_cast)
-BOOST_DEFUN([Conversion],
-[BOOST_FIND_HEADER([boost/cast.hpp])
-BOOST_FIND_HEADER([boost/lexical_cast.hpp])
-])# BOOST_CONVERSION
-
-
 # BOOST_COROUTINE([PREFERRED-RT-OPT], [ERROR_ON_UNUSABLE])
 # -----------------------------------
 # Look for Boost.Coroutine.  For the documentation of PREFERRED-RT-OPT, see the
diff --git a/modules/lua2backend/lua2api2.hh b/modules/lua2backend/lua2api2.hh
index 857fb1782c4a6..ba744da99a20f 100644
--- a/modules/lua2backend/lua2api2.hh
+++ b/modules/lua2backend/lua2api2.hh
@@ -20,7 +20,6 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 #pragma once
-#include "boost/lexical_cast.hpp"
 #include "boost/algorithm/string/join.hpp"
 #include "pdns/arguments.hh"
 
diff --git a/pdns/dnsdistdist/dnsdist-lua-bindings-packetcache.cc b/pdns/dnsdistdist/dnsdist-lua-bindings-packetcache.cc
index 30a09d6c4c24d..6ca827af2ad07 100644
--- a/pdns/dnsdistdist/dnsdist-lua-bindings-packetcache.cc
+++ b/pdns/dnsdistdist/dnsdist-lua-bindings-packetcache.cc
@@ -28,8 +28,6 @@
 #include "dnsdist-cache.hh"
 #include "dnsdist-lua.hh"
 
-#include <boost/lexical_cast.hpp>
-
 void setupLuaBindingsPacketCache(LuaContext& luaCtx, bool client)
 {
   /* PacketCache */