diff --git a/changelogs/fragments/56038-fix-non-signature-auth.yaml b/changelogs/fragments/56038-fix-non-signature-auth.yaml
new file mode 100644
index 00000000000..ea4413757fd
--- /dev/null
+++ b/changelogs/fragments/56038-fix-non-signature-auth.yaml
@@ -0,0 +1,2 @@
+bugfixes:
+- ACI modules - Fix non-signature authentication
diff --git a/lib/ansible/module_utils/network/aci/aci.py b/lib/ansible/module_utils/network/aci/aci.py
index bb58f12a938..29498527c74 100644
--- a/lib/ansible/module_utils/network/aci/aci.py
+++ b/lib/ansible/module_utils/network/aci/aci.py
@@ -335,7 +335,7 @@ class ACIModule(object):
             self.url = '%(protocol)s://%(host)s/' % self.params + path.lstrip('/')
 
         # Sign and encode request as to APIC's wishes
-        if not self.params['private_key']:
+        if self.params['private_key']:
             self.cert_auth(path=path, payload=payload)
 
         # Perform request
@@ -372,7 +372,7 @@ class ACIModule(object):
             self.url = '%(protocol)s://%(host)s/' % self.params + path.lstrip('/')
 
         # Sign and encode request as to APIC's wishes
-        if not self.params['private_key']:
+        if self.params['private_key']:
             self.cert_auth(path=path, method='GET')
 
         # Perform request
@@ -659,7 +659,7 @@ class ACIModule(object):
 
         elif not self.module.check_mode:
             # Sign and encode request as to APIC's wishes
-            if not self.params['private_key']:
+            if self.params['private_key']:
                 self.cert_auth(method='DELETE')
 
             resp, info = fetch_url(self.module, self.url,
@@ -795,7 +795,7 @@ class ACIModule(object):
         uri = self.url + self.filter_string
 
         # Sign and encode request as to APIC's wishes
-        if not self.params['private_key']:
+        if self.params['private_key']:
             self.cert_auth(path=self.path + self.filter_string, method='GET')
 
         resp, info = fetch_url(self.module, uri,
@@ -896,7 +896,7 @@ class ACIModule(object):
             return
         elif not self.module.check_mode:
             # Sign and encode request as to APIC's wishes
-            if not self.params['private_key']:
+            if self.params['private_key']:
                 self.cert_auth(method='POST', payload=json.dumps(self.config))
 
             resp, info = fetch_url(self.module, self.url,