diff --git a/include/boost/parser/lexer.hpp b/include/boost/parser/lexer.hpp
index d2052a1a..d88112b4 100644
--- a/include/boost/parser/lexer.hpp
+++ b/include/boost/parser/lexer.hpp
@@ -13,6 +13,10 @@
     "In order to work, the Boost.Parser lexer requires C++20 and CTRE's ctre-unicode.hpp single-header file in the #include path.  CTRE can be found at https://github.com/hanickadot/compile-time-regular-expressions .  The required header is at https://raw.githubusercontent.com/hanickadot/compile-time-regular-expressions/refs/heads/main/single-header/ctre-unicode.hpp ."
 #endif
 
+#if defined(BOOST_PARSER_PARSER_HPP)
+#error "lexer.hpp must be included before parser.hpp."
+#endif
+
 #include <boost/parser/parser_fwd.hpp>
 #include <boost/parser/concepts.hpp>
 #include <boost/parser/detail/debug_assert.hpp>
@@ -977,6 +981,4 @@ namespace boost { namespace parser {
 
 }}
 
-#include <boost/parser/token_parser.hpp>
-
 #endif
diff --git a/include/boost/parser/parser.hpp b/include/boost/parser/parser.hpp
index 54b16347..738669e8 100644
--- a/include/boost/parser/parser.hpp
+++ b/include/boost/parser/parser.hpp
@@ -8623,6 +8623,9 @@ namespace boost { namespace parser {
 
 }}
 
+#if defined(BOOST_PARSER_LEXER_HPP)
+#include <boost/parser/token_parser.hpp>
+#endif
 #include <boost/parser/detail/printing_impl.hpp>
 
 namespace boost { namespace parser {
@@ -9551,6 +9554,4 @@ namespace boost { namespace parser {
     }
 }}
 
-#include <boost/parser/token_parser.hpp>
-
 #endif
diff --git a/include/boost/parser/token_parser.hpp b/include/boost/parser/token_parser.hpp
index 6ad2cb7f..3d729813 100644
--- a/include/boost/parser/token_parser.hpp
+++ b/include/boost/parser/token_parser.hpp
@@ -4,9 +4,12 @@
 // accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
 #ifndef BOOST_PARSER_TOKEN_PARSER_HPP
-#if defined(BOOST_PARSER_PARSER_HPP) && defined(BOOST_PARSER_LEXER_HPP)
 #define BOOST_PARSER_TOKEN_PARSER_HPP
 
+#if !defined(BOOST_PARSER_PARSER_HPP) || !defined(BOOST_PARSER_LEXER_HPP)
+#error "token_parser.hpp must be included after lexer.hpp and parser.hpp."
+#endif
+
 #include <boost/parser/parser_fwd.hpp>
 #include <boost/parser/concepts.hpp>
 #include <boost/parser/error_handling.hpp>
@@ -237,4 +240,3 @@ namespace boost { namespace parser {
 }}
 
 #endif
-#endif
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 878c8c49..b4235315 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -49,7 +49,6 @@ add_test(NAME parser_api COMMAND parser_api)
 add_executable(
     compile_tests
     compile_include_lexer_parser.cpp
-    compile_include_parser_lexer.cpp
     compile_tests_main.cpp
     compile_attribute.cpp
     compile_seq_attribute.cpp
diff --git a/test/compile_include_parser_lexer.cpp b/test/compile_include_parser_lexer.cpp
deleted file mode 100644
index 343b1988..00000000
--- a/test/compile_include_parser_lexer.cpp
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright (C) 2024 T. Zachary Laine
-//
-// Distributed under the Boost Software License, Version 1.0. (See
-// accompanying file LICENSE_1_0.txt or copy at
-// http://www.boost.org/LICENSE_1_0.txt)
-#include <boost/parser/parser.hpp>
-#if BOOST_PARSER_USE_CONCEPTS
-#include <boost/parser/lexer.hpp>
-#endif
diff --git a/test/lexer_and_parser.cpp b/test/lexer_and_parser.cpp
index 71cbed65..50a34ced 100644
--- a/test/lexer_and_parser.cpp
+++ b/test/lexer_and_parser.cpp
@@ -6,8 +6,8 @@
  *   http://www.boost.org/LICENSE_1_0.txt)
  */
 
-#include <boost/parser/parser.hpp>
 #include <boost/parser/lexer.hpp>
+#include <boost/parser/parser.hpp>
 
 #include <boost/core/lightweight_test.hpp>