diff --git a/src/registrar/admin.py b/src/registrar/admin.py
index 667648a3c..41d3a56fb 100644
--- a/src/registrar/admin.py
+++ b/src/registrar/admin.py
@@ -1173,7 +1173,7 @@ class DomainInformationAdmin(ListHeaderAdmin, ImportExportModelAdmin):
     ]
 
     # Readonly fields for analysts and superusers
-    readonly_fields = ("other_contacts", "generic_org_type", "is_election_board")
+    readonly_fields = ("other_contacts", "generic_org_type", "is_election_board", "federal_agency")
 
     # Read only that we'll leverage for CISA Analysts
     analyst_readonly_fields = [
@@ -1440,6 +1440,7 @@ class DomainRequestAdmin(ListHeaderAdmin, ImportExportModelAdmin):
         "alternative_domains",
         "generic_org_type",
         "is_election_board",
+        "federal_agency",
     )
 
     # Read only that we'll leverage for CISA Analysts
@@ -1881,7 +1882,7 @@ class DomainAdmin(ListHeaderAdmin, ImportExportModelAdmin):
     search_fields = ["name"]
     search_help_text = "Search by domain name."
     change_form_template = "django/admin/domain_change_form.html"
-    readonly_fields = ["state", "expiration_date", "first_ready", "deleted"]
+    readonly_fields = ("state", "expiration_date", "first_ready", "deleted", "federal_agency")
 
     # Table ordering
     ordering = ["name"]
diff --git a/src/registrar/tests/test_admin.py b/src/registrar/tests/test_admin.py
index 0a1bd1361..e65d3d4c4 100644
--- a/src/registrar/tests/test_admin.py
+++ b/src/registrar/tests/test_admin.py
@@ -2232,6 +2232,7 @@ class TestDomainRequestAdmin(MockEppLib):
                 "alternative_domains",
                 "generic_org_type",
                 "is_election_board",
+                "federal_agency",
                 "id",
                 "created_at",
                 "updated_at",
@@ -2286,6 +2287,7 @@ class TestDomainRequestAdmin(MockEppLib):
                 "alternative_domains",
                 "generic_org_type",
                 "is_election_board",
+                "federal_agency",
                 "creator",
                 "about_your_organization",
                 "requested_domain",
@@ -2314,6 +2316,7 @@ class TestDomainRequestAdmin(MockEppLib):
                 "alternative_domains",
                 "generic_org_type",
                 "is_election_board",
+                "federal_agency",
             ]
 
             self.assertEqual(readonly_fields, expected_fields)
@@ -3172,6 +3175,7 @@ class TestDomainInformationAdmin(TestCase):
                 "other_contacts",
                 "generic_org_type",
                 "is_election_board",
+                "federal_agency",
                 "creator",
                 "type_of_work",
                 "more_organization_information",