diff --git a/types/joi/index.d.ts b/types/joi/index.d.ts
index 12aa17b643..9456fc5b64 100644
--- a/types/joi/index.d.ts
+++ b/types/joi/index.d.ts
@@ -714,6 +714,7 @@ export interface ArraySchema extends AnySchema {
      * Specifies the exact number of items in the array.
      */
     length(limit: number): this;
+    length(limit: Reference): this;
 
     /**
      * Requires the array values to be unique.
diff --git a/types/joi/joi-tests.ts b/types/joi/joi-tests.ts
index def9eaafd4..392247fa5e 100644
--- a/types/joi/joi-tests.ts
+++ b/types/joi/joi-tests.ts
@@ -318,6 +318,7 @@ arrSchema = arrSchema.ordered([schemaMap, schemaMap, schemaLike]);
 arrSchema = arrSchema.min(num);
 arrSchema = arrSchema.max(num);
 arrSchema = arrSchema.length(num);
+arrSchema = arrSchema.length(ref);
 arrSchema = arrSchema.unique();
 arrSchema = arrSchema.unique((a, b) => a.test === b.test);
 arrSchema = arrSchema.unique('customer.id');
diff --git a/types/joi/v10/index.d.ts b/types/joi/v10/index.d.ts
index e21edda875..e8202d77dd 100644
--- a/types/joi/v10/index.d.ts
+++ b/types/joi/v10/index.d.ts
@@ -670,6 +670,7 @@ export interface ArraySchema extends AnySchema {
      * Specifies the exact number of items in the array.
      */
     length(limit: number): this;
+    length(limit: Reference): this;
 
     /**
      * Requires the array values to be unique.
diff --git a/types/joi/v10/joi-tests.ts b/types/joi/v10/joi-tests.ts
index b1f125a6ea..e1194f5b76 100644
--- a/types/joi/v10/joi-tests.ts
+++ b/types/joi/v10/joi-tests.ts
@@ -299,6 +299,7 @@ arrSchema = arrSchema.ordered([schemaMap, schemaMap, schemaLike]);
 arrSchema = arrSchema.min(num);
 arrSchema = arrSchema.max(num);
 arrSchema = arrSchema.length(num);
+arrSchema = arrSchema.length(ref);
 arrSchema = arrSchema.unique();
 arrSchema = arrSchema.unique((a, b) => a.test === b.test);
 arrSchema = arrSchema.unique('customer.id');