diff --git a/bigquery/storage/managedwriter/adapt/protoconversion.go b/bigquery/storage/managedwriter/adapt/protoconversion.go
index c1c264dfc978..63b81e5072fd 100644
--- a/bigquery/storage/managedwriter/adapt/protoconversion.go
+++ b/bigquery/storage/managedwriter/adapt/protoconversion.go
@@ -63,6 +63,27 @@ var bqTypeToFieldTypeMap = map[storagepb.TableFieldSchema_Type]descriptorpb.Fiel
 	storagepb.TableFieldSchema_TIMESTAMP:  descriptorpb.FieldDescriptorProto_TYPE_INT64,
 }
 
+// Primitive types which can leverage packed encoding when repeated/arrays.
+//
+// Note: many/most of these aren't used when doing schema to proto conversion, but
+// are included for completeness.
+var packedTypes = []descriptorpb.FieldDescriptorProto_Type{
+	descriptorpb.FieldDescriptorProto_TYPE_INT32,
+	descriptorpb.FieldDescriptorProto_TYPE_INT64,
+	descriptorpb.FieldDescriptorProto_TYPE_UINT32,
+	descriptorpb.FieldDescriptorProto_TYPE_UINT64,
+	descriptorpb.FieldDescriptorProto_TYPE_SINT32,
+	descriptorpb.FieldDescriptorProto_TYPE_SINT64,
+	descriptorpb.FieldDescriptorProto_TYPE_FIXED32,
+	descriptorpb.FieldDescriptorProto_TYPE_FIXED64,
+	descriptorpb.FieldDescriptorProto_TYPE_SFIXED32,
+	descriptorpb.FieldDescriptorProto_TYPE_SFIXED64,
+	descriptorpb.FieldDescriptorProto_TYPE_FLOAT,
+	descriptorpb.FieldDescriptorProto_TYPE_DOUBLE,
+	descriptorpb.FieldDescriptorProto_TYPE_BOOL,
+	descriptorpb.FieldDescriptorProto_TYPE_ENUM,
+}
+
 // For TableFieldSchema OPTIONAL mode, we use the wrapper types to allow for the
 // proper representation of NULL values, as proto3 semantics would just use default value.
 var bqTypeToWrapperMap = map[storagepb.TableFieldSchema_Type]string{
@@ -85,7 +106,7 @@ var wellKnownTypesWrapperName = "google/protobuf/wrappers.proto"
 
 // dependencyCache is used to reduce the number of unique messages we generate by caching based on the tableschema.
 //
-// keys are based on the base64-encoded serialized tableschema value.
+// Keys are based on the base64-encoded serialized tableschema value.
 type dependencyCache map[string]protoreflect.MessageDescriptor
 
 func (dm dependencyCache) get(schema *storagepb.TableSchema) protoreflect.MessageDescriptor {
@@ -143,7 +164,7 @@ func StorageSchemaToProto3Descriptor(inSchema *storagepb.TableSchema, scope stri
 	return storageSchemaToDescriptorInternal(inSchema, scope, &dc, true)
 }
 
-// internal implementation of the conversion code.
+// Internal implementation of the conversion code.
 func storageSchemaToDescriptorInternal(inSchema *storagepb.TableSchema, scope string, cache *dependencyCache, useProto3 bool) (protoreflect.MessageDescriptor, error) {
 	if inSchema == nil {
 		return nil, newConversionError(scope, fmt.Errorf("no input schema was provided"))
@@ -170,11 +191,11 @@ func storageSchemaToDescriptorInternal(inSchema *storagepb.TableSchema, scope st
 						break
 					}
 				}
-				// if dep is missing, add to current dependencies
+				// If dep is missing, add to current dependencies.
 				if !haveDep {
 					deps = append(deps, foundDesc.ParentFile())
 				}
-				// construct field descriptor for the message
+				// Construct field descriptor for the message.
 				fdp, err := tableFieldSchemaToFieldDescriptorProto(f, fNumber, string(foundDesc.FullName()), useProto3)
 				if err != nil {
 					return nil, newConversionError(scope, fmt.Errorf("couldn't convert field to FieldDescriptorProto: %w", err))
@@ -277,12 +298,25 @@ func tableFieldSchemaToFieldDescriptorProto(field *storagepb.TableFieldSchema, i
 
 	// For (REQUIRED||REPEATED) fields for proto3, or all cases for proto2, we can use the expected scalar types.
 	if field.GetMode() != storagepb.TableFieldSchema_NULLABLE || !useProto3 {
-		return &descriptorpb.FieldDescriptorProto{
+		outType := bqTypeToFieldTypeMap[field.GetType()]
+		fdp := &descriptorpb.FieldDescriptorProto{
 			Name:   proto.String(name),
 			Number: proto.Int32(idx),
-			Type:   bqTypeToFieldTypeMap[field.GetType()].Enum(),
+			Type:   outType.Enum(),
 			Label:  convertModeToLabel(field.GetMode(), useProto3),
-		}, nil
+		}
+		// Special case: proto2 repeated fields may benefit from using packed annotation.
+		if field.GetMode() == storagepb.TableFieldSchema_REPEATED && !useProto3 {
+			for _, v := range packedTypes {
+				if outType == v {
+					fdp.Options = &descriptorpb.FieldOptions{
+						Packed: proto.Bool(true),
+					}
+					break
+				}
+			}
+		}
+		return fdp, nil
 	}
 	// For NULLABLE proto3 fields, use a wrapper type.
 	return &descriptorpb.FieldDescriptorProto{
@@ -445,7 +479,7 @@ func normalizeName(in string) string {
 	return strings.Replace(in, ".", "_", -1)
 }
 
-// these types don't get normalized into the fully-contained structure.
+// These types don't get normalized into the fully-contained structure.
 var normalizationSkipList = []string{
 	/*
 		TODO: when backend supports resolving well known types, this list should be enabled.
diff --git a/bigquery/storage/managedwriter/adapt/protoconversion_test.go b/bigquery/storage/managedwriter/adapt/protoconversion_test.go
index aaf6b4cb6630..8444b6f0d38d 100644
--- a/bigquery/storage/managedwriter/adapt/protoconversion_test.go
+++ b/bigquery/storage/managedwriter/adapt/protoconversion_test.go
@@ -384,6 +384,35 @@ func TestSchemaToProtoConversion(t *testing.T) {
 				},
 			},
 		},
+		{
+			description: "repeated w/packed",
+			bq: &storagepb.TableSchema{
+				Fields: []*storagepb.TableFieldSchema{
+					{Name: "name", Type: storagepb.TableFieldSchema_STRING, Mode: storagepb.TableFieldSchema_NULLABLE},
+					{Name: "some_lengths", Type: storagepb.TableFieldSchema_INT64, Mode: storagepb.TableFieldSchema_REPEATED},
+					{Name: "nicknames", Type: storagepb.TableFieldSchema_STRING, Mode: storagepb.TableFieldSchema_REPEATED},
+				}},
+			wantProto2: &descriptorpb.DescriptorProto{
+				Name: proto.String("root"),
+				Field: []*descriptorpb.FieldDescriptorProto{
+					{
+						Name:   proto.String("name"),
+						Number: proto.Int32(1),
+						Type:   descriptorpb.FieldDescriptorProto_TYPE_STRING.Enum(),
+						Label:  descriptorpb.FieldDescriptorProto_LABEL_OPTIONAL.Enum()},
+					{
+						Name:   proto.String("some_lengths"),
+						Number: proto.Int32(2),
+						Type:   descriptorpb.FieldDescriptorProto_TYPE_INT64.Enum(),
+						Label:  descriptorpb.FieldDescriptorProto_LABEL_REPEATED.Enum(),
+						Options: &descriptorpb.FieldOptions{
+							Packed: proto.Bool(true),
+						},
+					},
+					{Name: proto.String("nicknames"), Number: proto.Int32(3), Type: descriptorpb.FieldDescriptorProto_TYPE_STRING.Enum(), Label: descriptorpb.FieldDescriptorProto_LABEL_REPEATED.Enum()},
+				},
+			},
+		},
 	}
 	for _, tc := range testCases {
 		// Proto2