diff --git a/src/common.cpp b/src/common.cpp
index 6e17c9a..8e90cb6 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -692,6 +692,31 @@ Result<Value> Array::get(const Value& key) const {
   return get(key.to<Int64>()->value());
 }
 
+Result<Array> Array::set(uint64_t idx, const Value& value) const {
+  uint64_t res_size = TRY(size());
+  if (idx >= res_size) return ERROR(IndexOutOfRange);
+
+  auto pod = TRY(arena_alloc<PodArray>(res_size * sizeof(OffPtr<PodObject>)));
+  pod->header.tag = Tag::Array;
+  pod->size = res_size;
+  for (uint64_t i = 0; i < res_size; i++) {
+    pod->data[i] = _value->data[i].get();
+  }
+  pod->data[idx] = value.pod();
+
+  return Array(TRY(MkGcRoot(pod)));
+}
+
+Result<Array> Array::set(const Value& key, const Value& value) const {
+  if (!key.is<Int64>()) return ERROR(TypeMismatch);
+
+  return set(key.to<Int64>()->value(), value);
+}
+
+Result<Value> Array::set_value(const Value& key, const Value& value) const {
+  return Value(TRY(set(key, value)));
+}
+
 Result<Array> Array::append(const Value& rhs) const {
   uint64_t res_size = TRY(size()) + 1;
   auto size = TRY(this->size());
diff --git a/src/common.hpp b/src/common.hpp
index be57978..0fc5d17 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -210,6 +210,10 @@ class Array : public Object {
 
   Result<Value> get(uint64_t idx) const;
   virtual Result<Value> get(const Value& key) const final;
+  Result<Array> set(uint64_t idx, const Value& value) const;
+  Result<Array> set(const Value& key, const Value& value) const;
+  virtual Result<Value> set_value(const Value& key,
+                                  const Value& value) const final;
 
   Result<Array> append(const Value& rhs) const;
   template <class V>
diff --git a/test/collections.vli b/test/collections.vli
index 1f0f616..0fe25ef 100644
--- a/test/collections.vli
+++ b/test/collections.vli
@@ -10,6 +10,12 @@
 (assert (= (get {1 2 3 4} 3)
            4))
 
+(assert (= (set {:foo 1} :bar 2)
+           {:foo 1 :bar 2}))
+
+(assert (= (set [1 2] 1 42)
+           [1 42]))
+
 ;; Accessing collections by symbol
 (assert (= (get {:foo 1 :bar 2} :bar)
            2))