diff --git a/changelogs/fragments/1293-added-primary-ip4-netmask-to-output.yml b/changelogs/fragments/1293-added-primary-ip4-netmask-to-output.yml
new file mode 100755
index 000000000..97db13277
--- /dev/null
+++ b/changelogs/fragments/1293-added-primary-ip4-netmask-to-output.yml
@@ -0,0 +1,2 @@
+minor_changes:
+  - Adds the ability to return ``primary_ip4_netmask`` for virtual machines in nb_inventory plugin.
diff --git a/plugins/inventory/nb_inventory.py b/plugins/inventory/nb_inventory.py
index 03444b6b4..b4a29ab7f 100644
--- a/plugins/inventory/nb_inventory.py
+++ b/plugins/inventory/nb_inventory.py
@@ -840,6 +840,13 @@ def extract_primary_ip4(self, host):
         except Exception:
             return
 
+    def extract_primary_ip4_netmask(self, host):
+        try:
+            address = host["primary_ip4"]["address"]
+            return str(ip_interface(address).netmask)
+        except Exception:
+            return
+
     def extract_primary_ip6(self, host):
         try:
             address = host["primary_ip6"]["address"]
@@ -1938,6 +1945,12 @@ def _fill_host_variables(self, host, hostname):
         if extracted_primary_ip4:
             self._set_variable(hostname, "primary_ip4", extracted_primary_ip4)
 
+        extracted_primary_ip4_netmask = self.extract_primary_ip4_netmask(host=host)
+        if extracted_primary_ip4_netmask:
+            self._set_variable(
+                hostname, "primary_ip4_netmask", extracted_primary_ip4_netmask
+            )
+
         extracted_primary_ip6 = self.extract_primary_ip6(host=host)
         if extracted_primary_ip6:
             self._set_variable(hostname, "primary_ip6", extracted_primary_ip6)