diff --git a/cpp/src/arrow/compute/exec.cc b/cpp/src/arrow/compute/exec.cc
index 411ff0bb026..042240b3edf 100644
--- a/cpp/src/arrow/compute/exec.cc
+++ b/cpp/src/arrow/compute/exec.cc
@@ -783,7 +783,14 @@ class ScalarExecutor : public KernelExecutorImpl<ScalarKernel> {
   Status Execute(const ExecBatch& batch, ExecListener* listener) override {
     RETURN_NOT_OK(span_iterator_.Init(batch, exec_context()->exec_chunksize()));
 
-    if (batch.length == 0) {
+    // A dictionary-to-dictionary cast must run to preserve unreferenced dictionary
+    // values even when there are no indices to process.
+    const bool changes_dictionary_type =
+        batch.num_values() == 1 && batch.values[0].type() != nullptr &&
+        is_dictionary(batch.values[0].type()->id()) &&
+        is_dictionary(output_type_.type->id()) &&
+        !batch.values[0].type()->Equals(*output_type_.type);
+    if (batch.length == 0 && !changes_dictionary_type) {
       // For zero-length batches, we do nothing except return a zero-length
       // array of the correct output type
       ARROW_ASSIGN_OR_RAISE(std::shared_ptr<Array> result,
diff --git a/cpp/src/arrow/compute/kernels/scalar_cast_test.cc b/cpp/src/arrow/compute/kernels/scalar_cast_test.cc
index 364a4bd436b..f5005cb43ce 100644
--- a/cpp/src/arrow/compute/kernels/scalar_cast_test.cc
+++ b/cpp/src/arrow/compute/kernels/scalar_cast_test.cc
@@ -4573,6 +4573,19 @@ TEST(Cast, DictTypeToAnotherDict) {
       Cast(arr, dictionary(int8(), int8()), CastOptions::Safe()));
 }
 
+TEST(Cast, EmptyDictionaryToAnotherDictionary) {
+  auto dictionary_values = ArrayFromJSON(utf8(), R"(["foo", "bar"])");
+
+  ASSERT_OK_AND_ASSIGN(auto input, DictionaryArray::FromArrays(
+                                       dictionary(int32(), utf8()),
+                                       ArrayFromJSON(int32(), "[]"), dictionary_values));
+  ASSERT_OK_AND_ASSIGN(auto result, Cast(*input, dictionary(int64(), utf8())));
+  auto dictionary_result = checked_pointer_cast<DictionaryArray>(result);
+
+  ASSERT_TRUE(dictionary_result->indices()->type()->Equals(int64()));
+  AssertArraysEqual(*dictionary_values, *dictionary_result->dictionary());
+}
+
 TEST(Cast, NoOutBitmapIfInIsAllValid) {
   auto a = ArrayFromJSON(int8(), "[1]");
   CastOptions options;