diff --git a/changelogs/fragments/858-postgresql_privs_should_allow_public_role_lowercased.yml b/changelogs/fragments/858-postgresql_privs_should_allow_public_role_lowercased.yml
new file mode 100644
index 0000000000..1e51ec729b
--- /dev/null
+++ b/changelogs/fragments/858-postgresql_privs_should_allow_public_role_lowercased.yml
@@ -0,0 +1,2 @@
+bugfixes:
+- postgresql_privs - allow to pass ``PUBLIC`` role written in lowercase letters (https://github.com/ansible-collections/community.general/issues/857).
diff --git a/plugins/modules/database/postgresql/postgresql_privs.py b/plugins/modules/database/postgresql/postgresql_privs.py
index 989279e9ed..30f2de7988 100644
--- a/plugins/modules/database/postgresql/postgresql_privs.py
+++ b/plugins/modules/database/postgresql/postgresql_privs.py
@@ -169,6 +169,7 @@ notes:
   C(present) and I(grant_option) to C(no) (see examples).
 - Note that when revoking privileges from a role R, this role  may still have
   access via privileges granted to any role R is a member of including C(PUBLIC).
+- Note that when you use C(PUBLIC) role, the module always reports that the state has been changed.
 - Note that when revoking privileges from a role R, you do so as the user
   specified via I(login). If R has been granted the same privileges by
   another user also, R can still access database objects via these privileges.
@@ -783,6 +784,9 @@ class Connection(object):
 
         executed_queries.append(query)
         self.cursor.execute(query)
+        if roles == 'PUBLIC':
+            return True
+
         status_after = get_status(objs)
 
         def nonesorted(e):
@@ -1053,7 +1057,7 @@ def main():
                 objs = [obj.replace(':', ',') for obj in objs]
 
         # roles
-        if p.roles == 'PUBLIC':
+        if p.roles.upper() == 'PUBLIC':
             roles = 'PUBLIC'
         else:
             roles = p.roles.split(',')
diff --git a/tests/integration/targets/postgresql_privs/tasks/postgresql_privs_initial.yml b/tests/integration/targets/postgresql_privs/tasks/postgresql_privs_initial.yml
index e2b06c21c7..8aa6b409ff 100644
--- a/tests/integration/targets/postgresql_privs/tasks/postgresql_privs_initial.yml
+++ b/tests/integration/targets/postgresql_privs/tasks/postgresql_privs_initial.yml
@@ -343,6 +343,23 @@
     target_roles: "{{ db_user_with_dots2 }}"
     trust_input: no
 
+# Bugfix for https://github.com/ansible-collections/community.general/issues/857
+- name: Test passing lowercase PUBLIC role
+  become_user: "{{ pg_user }}"
+  become: yes
+  postgresql_privs:
+    db: "{{ db_name }}"
+    login_user: "{{ pg_user }}"
+    type: 'database'
+    privs: 'connect'
+    role: 'public'
+  register: result
+
+- assert:
+    that:
+    - result is changed
+    - result.queries == ["GRANT CONNECT ON database \"{{ db_name }}\" TO PUBLIC;"]
+
 #
 # Cleanup
 #