diff --git a/go.mod b/go.mod
index a28ae8f..7b75538 100644
--- a/go.mod
+++ b/go.mod
@@ -60,6 +60,7 @@ require (
 	golang.org/x/crypto v0.54.0 // indirect
 	golang.org/x/exp v0.0.0-20250305212735-054e65f0b394 // indirect
 	golang.org/x/net v0.57.0 // indirect
+	golang.org/x/sync v0.22.0 // indirect
 	golang.org/x/sys v0.47.0 // indirect
 	golang.org/x/term v0.45.0 // indirect
 	golang.org/x/text v0.40.0 // indirect
diff --git a/internal/agent/files.go b/internal/agent/files.go
index 03f8a70..ea6de8f 100644
--- a/internal/agent/files.go
+++ b/internal/agent/files.go
@@ -8,21 +8,40 @@ import (
 	"time"
 
 	"github.com/google/research-cli/internal/utils"
+	"golang.org/x/sync/errgroup"
 	"google.golang.org/genai"
 )
 
 func (a *ResearchAgent) UploadFiles(ctx context.Context, filePaths []string) ([]string, error) {
-	var uris []string
-	for _, path := range filePaths {
-		uri, err := a.uploadFile(ctx, path)
-		if err != nil {
-			return nil, fmt.Errorf("failed to upload %s: %w", path, err)
-		}
+	if len(filePaths) == 0 {
+		return nil, nil
+	}
+
+	g, ctx := errgroup.WithContext(ctx)
+	uris := make([]string, len(filePaths))
+
+	for i, path := range filePaths {
+		g.Go(func() error {
+			uri, err := a.uploadFile(ctx, path)
+			if err != nil {
+				return fmt.Errorf("failed to upload %s: %w", path, err)
+			}
+			uris[i] = uri
+			return nil
+		})
+	}
+
+	if err := g.Wait(); err != nil {
+		return nil, err
+	}
+
+	result := make([]string, 0, len(uris))
+	for _, uri := range uris {
 		if uri != "" {
-			uris = append(uris, uri)
+			result = append(result, uri)
 		}
 	}
-	return uris, nil
+	return result, nil
 }
 
 func (a *ResearchAgent) uploadFile(ctx context.Context, path string) (string, error) {
diff --git a/internal/agent/files_test.go b/internal/agent/files_test.go
new file mode 100644
index 0000000..5d4e112
--- /dev/null
+++ b/internal/agent/files_test.go
@@ -0,0 +1,128 @@
+package agent
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"testing"
+	"time"
+
+	"golang.org/x/sync/errgroup"
+)
+
+type uploadFileFunc func(ctx context.Context, path string) (string, error)
+
+func uploadFilesSequential(ctx context.Context, filePaths []string, uploadFn uploadFileFunc) ([]string, error) {
+	var uris []string
+	for _, path := range filePaths {
+		uri, err := uploadFn(ctx, path)
+		if err != nil {
+			return nil, fmt.Errorf("failed to upload %s: %w", path, err)
+		}
+		if uri != "" {
+			uris = append(uris, uri)
+		}
+	}
+	return uris, nil
+}
+
+func uploadFilesConcurrent(ctx context.Context, filePaths []string, uploadFn uploadFileFunc) ([]string, error) {
+	if len(filePaths) == 0 {
+		return nil, nil
+	}
+
+	g, ctx := errgroup.WithContext(ctx)
+	uris := make([]string, len(filePaths))
+
+	for i, path := range filePaths {
+		g.Go(func() error {
+			uri, err := uploadFn(ctx, path)
+			if err != nil {
+				return fmt.Errorf("failed to upload %s: %w", path, err)
+			}
+			uris[i] = uri
+			return nil
+		})
+	}
+
+	if err := g.Wait(); err != nil {
+		return nil, err
+	}
+
+	result := make([]string, 0, len(uris))
+	for _, uri := range uris {
+		if uri != "" {
+			result = append(result, uri)
+		}
+	}
+	return result, nil
+}
+
+func TestUploadFilesConcurrentPreservesOrder(t *testing.T) {
+	paths := []string{"a.txt", "b.txt", "c.txt", "d.txt"}
+	mockUpload := func(ctx context.Context, path string) (string, error) {
+		if path == "a.txt" {
+			time.Sleep(30 * time.Millisecond)
+		} else {
+			time.Sleep(5 * time.Millisecond)
+		}
+		return "uri://" + path, nil
+	}
+
+	uris, err := uploadFilesConcurrent(t.Context(), paths, mockUpload)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	want := []string{"uri://a.txt", "uri://b.txt", "uri://c.txt", "uri://d.txt"}
+	if !reflect.DeepEqual(uris, want) {
+		t.Fatalf("got uris %v, want %v", uris, want)
+	}
+}
+
+func TestUploadFilesConcurrentErrorHandling(t *testing.T) {
+	paths := []string{"a.txt", "fail.txt", "c.txt"}
+	mockUpload := func(ctx context.Context, path string) (string, error) {
+		if path == "fail.txt" {
+			return "", fmt.Errorf("upload error")
+		}
+		return "uri://" + path, nil
+	}
+
+	_, err := uploadFilesConcurrent(t.Context(), paths, mockUpload)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+}
+
+func BenchmarkUploadFiles_Sequential(b *testing.B) {
+	paths := []string{"file1.txt", "file2.txt", "file3.txt", "file4.txt", "file5.txt"}
+	mockUpload := func(ctx context.Context, path string) (string, error) {
+		time.Sleep(10 * time.Millisecond)
+		return "uri://" + path, nil
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := uploadFilesSequential(context.Background(), paths, mockUpload)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkUploadFiles_Concurrent(b *testing.B) {
+	paths := []string{"file1.txt", "file2.txt", "file3.txt", "file4.txt", "file5.txt"}
+	mockUpload := func(ctx context.Context, path string) (string, error) {
+		time.Sleep(10 * time.Millisecond)
+		return "uri://" + path, nil
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := uploadFilesConcurrent(context.Background(), paths, mockUpload)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}