diff --git a/module_build_service/builder/KojiContentGenerator.py b/module_build_service/builder/KojiContentGenerator.py
index b633b04d..5da00039 100644
--- a/module_build_service/builder/KojiContentGenerator.py
+++ b/module_build_service/builder/KojiContentGenerator.py
@@ -465,6 +465,13 @@ class KojiContentGenerator(object):
         # Check each RPM in `self.rpms_dict` to find out if it can be included in mmd
         # for this architecture.
         for nevra, rpm in self.rpms_dict.items():
+            # Filter out RPMs which will never end up in final modulemd:
+            # - the architecture of an RPM is not multilib architecture for `arch`.
+            # - the architecture of an RPM is not the final mmd architecture.
+            # - the architecture of an RPM is not "noarch".
+            if rpm["arch"] not in multilib_arches and rpm["arch"] not in [arch, "noarch"]:
+                continue
+
             srpm = rpm["srpm_name"]
 
             # Skip the RPM if it is excluded on this arch or exclusive
diff --git a/tests/test_content_generator.py b/tests/test_content_generator.py
index b272f680..1595eb07 100644
--- a/tests/test_content_generator.py
+++ b/tests/test_content_generator.py
@@ -432,8 +432,10 @@ class TestBuild:
     def test_fill_in_rpms_list(self):
         self._add_test_rpm("dhcp-libs-12:4.3.5-5.module_2118aef6.x86_64", "dhcp")
         self._add_test_rpm("dhcp-libs-12:4.3.5-5.module_2118aef6.i686", "dhcp")
+        self._add_test_rpm("dhcp-libs-12:4.3.5-5.module_2118aef6.s390x", "dhcp")
         self._add_test_rpm("perl-Tangerine-12:4.3.5-5.module_2118aef6.x86_64", "perl-Tangerine")
         self._add_test_rpm("perl-Tangerine-12:4.3.5-5.module_2118aef6.i686", "perl-Tangerine")
+        self._add_test_rpm("perl-Tangerine-12:4.3.5-5.module_2118aef6.s390x", "perl-Tangerine")
 
         mmd = self.cg.module.mmd()
         mmd = self.cg._fill_in_rpms_list(mmd, "x86_64")