diff --git a/.changelog/1253.txt b/.changelog/1253.txt
new file mode 100644
index 00000000000..a43f5d8cb70
--- /dev/null
+++ b/.changelog/1253.txt
@@ -0,0 +1,3 @@
+```release-note:enhancement
+rulesets: add support for add operation to HTTP header configuration
+```
diff --git a/rulesets.go b/rulesets.go
index d460eb8fec7..29aa2dfd608 100644
--- a/rulesets.go
+++ b/rulesets.go
@@ -69,6 +69,7 @@ const (
 
 	RulesetRuleActionParametersHTTPHeaderOperationRemove RulesetRuleActionParametersHTTPHeaderOperation = "remove"
 	RulesetRuleActionParametersHTTPHeaderOperationSet    RulesetRuleActionParametersHTTPHeaderOperation = "set"
+	RulesetRuleActionParametersHTTPHeaderOperationAdd    RulesetRuleActionParametersHTTPHeaderOperation = "add"
 )
 
 // RulesetKindValues exposes all the available `RulesetKind` values as a slice
@@ -155,6 +156,7 @@ func RulesetRuleActionParametersHTTPHeaderOperationValues() []string {
 	return []string{
 		string(RulesetRuleActionParametersHTTPHeaderOperationRemove),
 		string(RulesetRuleActionParametersHTTPHeaderOperationSet),
+		string(RulesetRuleActionParametersHTTPHeaderOperationAdd),
 	}
 }