diff --git a/var/spack/repos/builtin/packages/doxygen/package.py b/var/spack/repos/builtin/packages/doxygen/package.py
index a39d8b4eeba..5084b16b10a 100644
--- a/var/spack/repos/builtin/packages/doxygen/package.py
+++ b/var/spack/repos/builtin/packages/doxygen/package.py
@@ -43,3 +43,13 @@ class Doxygen(CMakePackage):
     # https://github.com/Sleepyowl/doxygen/commit/6c380ba91ae41c6d5c409a5163119318932ae2a3?diff=unified
     # Also - https://github.com/doxygen/doxygen/pull/6588
     patch('shared_ptr.patch', when='@1.8.14')
+
+    def patch(self):
+        # On Linux systems, iconv is provided by libc. Since CMake finds the
+        # symbol in libc, it does not look for libiconv, which leads to linker
+        # errors. This makes sure that CMake always looks for the external
+        # libconv instead.
+        filter_file('check_function_exists(iconv_open ICONV_IN_GLIBC)',
+                    'set(ICONV_IN_GLIBC FALSE)',
+                    join_path('cmake', 'FindIconv.cmake'),
+                    string=True)