diff --git a/.changelog/22284.txt b/.changelog/22284.txt
new file mode 100644
index 00000000000..07daacdf425
--- /dev/null
+++ b/.changelog/22284.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+resource/networkfirewall: allow any character in networkfirewall/ip_sets as per the AWS apis docs
+```
diff --git a/internal/service/networkfirewall/rule_group.go b/internal/service/networkfirewall/rule_group.go
index 25c5421f7f1..a5cf7fc4753 100644
--- a/internal/service/networkfirewall/rule_group.go
+++ b/internal/service/networkfirewall/rule_group.go
@@ -87,10 +87,7 @@ func ResourceRuleGroup() *schema.Resource {
 															"definition": {
 																Type:     schema.TypeSet,
 																Required: true,
-																Elem: &schema.Schema{
-																	Type:         schema.TypeString,
-																	ValidateFunc: verify.ValidIPv4CIDRNetworkAddress,
-																},
+																Elem: &schema.Schema{Type: schema.TypeString},
 															},
 														},
 													},