diff --git a/docs/config.md b/docs/config.md
index 119ba8b..884c959 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -850,6 +850,12 @@ Reply (with mention) to the selected message.
 
 Default: `"r"`
 
+### keybinds.messages_list.react
+
+Add an emoji reaction to the selected message.
+
+Default: `"a"`
+
 ### keybinds.messages_list.cancel
 
 Default: `"esc"`
diff --git a/internal/config/keybinds.go b/internal/config/keybinds.go
index 0c7d1ba..5c5de52 100644
--- a/internal/config/keybinds.go
+++ b/internal/config/keybinds.go
@@ -108,6 +108,8 @@ type MessagesListKeybinds struct {
 	Reply Keybind `toml:"reply"`
 	// Reply (with mention) to the selected message.
 	ReplyMention Keybind `toml:"reply_mention"`
+	// Add an emoji reaction to the selected message.
+	React Keybind `toml:"react"`
 
 	Cancel Keybind `toml:"cancel"`
 	Edit   Keybind `toml:"edit"`
@@ -275,6 +277,7 @@ func defaultKeybinds() Keybinds {
 			SelectReply:  key("sel reply", "s"),
 			Reply:        key("reply", "R"),
 			ReplyMention: key("@reply", "r"),
+			React:        key("react", "a"),
 
 			Cancel: key("cancel", "esc"),
 			Edit:   key("edit", "e"),
diff --git a/internal/emoji/emoji.go b/internal/emoji/emoji.go
index 025089a..716b57d 100644
--- a/internal/emoji/emoji.go
+++ b/internal/emoji/emoji.go
@@ -10,12 +10,20 @@ import (
 )
 
 type Item struct {
+	ID         discord.EmojiID
 	Name       string
 	InsertText string
 	Display    string
 	Custom     bool
 }
 
+// APIEmoji returns the formatted API emoji identifier for reactions.
+func (i Item) APIEmoji() discord.APIEmoji {
+	if i.Custom && i.ID.IsValid() {
+		return discord.NewAPIEmoji(i.ID, i.Name)
+	}
+	return discord.APIEmoji(i.InsertText)
+}
 type itemList []Item
 
 func (l itemList) String(i int) string {
@@ -56,6 +64,7 @@ func Search(query string, custom []discord.Emoji, limit int) []Item {
 	customItems := make([]Item, 0, len(custom))
 	for _, e := range custom {
 		customItems = append(customItems, Item{
+			ID:         e.ID,
 			Name:       e.Name,
 			InsertText: e.String(),
 			Display:    ":" + e.Name + ":",
diff --git a/internal/ui/chat/emojipicker/model.go b/internal/ui/chat/emojipicker/model.go
new file mode 100644
index 0000000..c5c349e
--- /dev/null
+++ b/internal/ui/chat/emojipicker/model.go
@@ -0,0 +1,63 @@
+package emojipicker
+
+import (
+	"github.com/ayn2op/arikawa/v3/discord"
+	"github.com/ayn2op/discordo/internal/config"
+	"github.com/ayn2op/discordo/internal/emoji"
+	uipicker "github.com/ayn2op/discordo/internal/ui/picker"
+	"github.com/ayn2op/ningen/v3"
+	"github.com/ayn2op/tview"
+	"github.com/ayn2op/tview/picker"
+)
+
+type Model struct {
+	uipicker.Model
+	cfg *config.Config
+}
+
+func NewModel(cfg *config.Config) Model {
+	return Model{Model: uipicker.NewModel(cfg, "Add Reaction"), cfg: cfg}
+}
+
+var _ tview.Model[Model] = Model{}
+
+// View shows the picker in a box titled Add Reaction.
+func (m Model) View() tview.Widget {
+	return m.Model.View(func(item picker.Item) tview.Msg {
+		apiEmoji, ok := item.Reference.(discord.APIEmoji)
+		if !ok {
+			return nil
+		}
+		return SelectedMsg{Emoji: apiEmoji}
+	}, CancelMsg{})
+}
+
+func (m Model) Update(msg tview.Msg) (Model, tview.Cmd) {
+	var cmd tview.Cmd
+	m.Model, cmd = m.Model.Update(msg)
+	return m, cmd
+}
+
+// RefreshEmojis repopulates the picker with custom guild emojis and Unicode emojis.
+func (m *Model) RefreshEmojis(state *ningen.State, guildID discord.GuildID) {
+	var customEmojis []discord.Emoji
+	if state != nil && state.EmojiState != nil {
+		guilds, err := state.EmojiState.ForGuild(guildID)
+		if err == nil {
+			for _, g := range guilds {
+				customEmojis = append(customEmojis, g.Emojis...)
+			}
+		}
+	}
+
+	results := emoji.Search("", customEmojis, 2500)
+	items := make(picker.Items, 0, len(results))
+	for _, item := range results {
+		items = append(items, picker.Item{
+			Text:       item.Display,
+			FilterText: item.Name,
+			Reference:  item.APIEmoji(),
+		})
+	}
+	m.SetItems(items)
+}
diff --git a/internal/ui/chat/emojipicker/model_test.go b/internal/ui/chat/emojipicker/model_test.go
new file mode 100644
index 0000000..2e6c778
--- /dev/null
+++ b/internal/ui/chat/emojipicker/model_test.go
@@ -0,0 +1,39 @@
+package emojipicker
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/ayn2op/arikawa/v3/discord"
+	"github.com/ayn2op/arikawa/v3/state"
+	"github.com/ayn2op/arikawa/v3/state/store/defaultstore"
+	"github.com/ayn2op/discordo/internal/config"
+	"github.com/ayn2op/ningen/v3"
+	ningenEmoji "github.com/ayn2op/ningen/v3/states/emoji"
+)
+
+func TestEmojiPickerRefresh(t *testing.T) {
+	cfg, err := config.Load(filepath.Join(t.TempDir(), "config.toml"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	st := ningen.FromState(state.NewWithStore("", defaultstore.New()))
+	guildID := discord.GuildID(100)
+	st.EmojiState = ningenEmoji.NewState(st.Cabinet)
+	_ = st.Cabinet.GuildSet(&discord.Guild{ID: guildID}, false)
+	_ = st.Cabinet.EmojiSet(guildID, []discord.Emoji{
+		{ID: 555, Name: "custom_pepe"},
+	}, false)
+
+	p := NewModel(cfg)
+	p.RefreshEmojis(st, guildID)
+
+	widget := p.View()
+	if widget == nil {
+		t.Fatal("expected non-nil view")
+	}
+
+	// Test Update
+	p, _ = p.Update(CancelMsg{})
+}
diff --git a/internal/ui/chat/emojipicker/msg.go b/internal/ui/chat/emojipicker/msg.go
new file mode 100644
index 0000000..2b5a0af
--- /dev/null
+++ b/internal/ui/chat/emojipicker/msg.go
@@ -0,0 +1,10 @@
+package emojipicker
+
+import "github.com/ayn2op/arikawa/v3/discord"
+
+type (
+	SelectedMsg struct {
+		Emoji discord.APIEmoji
+	}
+	CancelMsg struct{}
+)
diff --git a/internal/ui/chat/messageslist/keymap.go b/internal/ui/chat/messageslist/keymap.go
index 2e0c0be..9cc7874 100644
--- a/internal/ui/chat/messageslist/keymap.go
+++ b/internal/ui/chat/messageslist/keymap.go
@@ -17,6 +17,7 @@ func (m Model) ShortHelp() []keybind.Keybind {
 	}
 
 	if selectedMessage, ok := m.selectedMessage(); ok {
+		help = append(help, cfg.React.Keybind)
 		if !ui.IsMe(m.state, selectedMessage.Author.ID) {
 			help = append(help, cfg.Reply.Keybind)
 		}
@@ -35,6 +36,7 @@ func (m Model) FullHelp() [][]keybind.Keybind {
 	cfg := m.cfg.Keybinds.MessagesList
 	var actions, manage, attachments []keybind.Keybind
 	if message, ok := m.selectedMessage(); ok {
+		actions = append(actions, cfg.React.Keybind)
 		mine := ui.IsMe(m.state, message.Author.ID)
 		if !mine {
 			actions = append(actions, cfg.Reply.Keybind, cfg.ReplyMention.Keybind)
diff --git a/internal/ui/chat/messageslist/model.go b/internal/ui/chat/messageslist/model.go
index 5327769..4240717 100644
--- a/internal/ui/chat/messageslist/model.go
+++ b/internal/ui/chat/messageslist/model.go
@@ -464,6 +464,8 @@ func (m Model) Update(msg tview.Msg) (Model, tview.Cmd) {
 			return m, m.seek(m.voiceStatus.Position + seekStep)
 		case keybind.Matches(msg, kbs.Download.Keybind):
 			return m, m.download()
+		case keybind.Matches(msg, kbs.React.Keybind):
+			return m, m.react()
 		case keybind.Matches(msg, kbs.Reply.Keybind):
 			return m, m.reply(false)
 		case keybind.Matches(msg, kbs.ReplyMention.Keybind):
diff --git a/internal/ui/chat/messageslist/model_test.go b/internal/ui/chat/messageslist/model_test.go
index 1fc5c02..e93581a 100644
--- a/internal/ui/chat/messageslist/model_test.go
+++ b/internal/ui/chat/messageslist/model_test.go
@@ -401,3 +401,20 @@ func TestModelReactionsView(t *testing.T) {
 		}
 	})
 }
+
+func TestModelReact(t *testing.T) {
+	ml := newTestModel(t, testConfig(t))
+	msg := discord.Message{ID: 10, ChannelID: 1}
+	ml.items = []messageItem{{message: msg}}
+	ml.cursor = 0
+
+	cmd := ml.react()
+	if cmd == nil {
+		t.Fatal("expected non-nil cmd for react()")
+	}
+	result := cmd()
+	reactMsg, ok := result.(ReactMsg)
+	if !ok || reactMsg.Message.ID != 10 {
+		t.Fatalf("result = %v, want ReactMsg with ID 10", result)
+	}
+}
diff --git a/internal/ui/chat/messageslist/msg.go b/internal/ui/chat/messageslist/msg.go
index 3a27371..899f9ab 100644
--- a/internal/ui/chat/messageslist/msg.go
+++ b/internal/ui/chat/messageslist/msg.go
@@ -25,6 +25,11 @@ import (
 // Msg is implemented by the messages the list sends itself, which must reach it whatever has the focus.
 type Msg interface{ messagesList() }
 
+// ReactMsg requests opening the reaction picker for the message.
+type ReactMsg struct {
+	Message discord.Message
+}
+
 type olderMessagesLoadedMsg struct {
 	channelID discord.ChannelID
 	older     []discord.Message
@@ -345,6 +350,15 @@ func (m Model) reply(mention bool) tview.Cmd {
 	return func() tview.Msg { return ReplyMsg{Message: message, Name: name, Mention: mention} }
 }
 
+func (m Model) react() tview.Cmd {
+	selectedMessage, ok := m.selectedMessage()
+	if !ok {
+		return nil
+	}
+	message := *selectedMessage
+	return func() tview.Msg { return ReactMsg{Message: message} }
+}
+
 func (m Model) editSelectedMessage() tview.Cmd {
 	selectedMessage, ok := m.selectedMessage()
 	if !ok {
diff --git a/internal/ui/chat/model.go b/internal/ui/chat/model.go
index 379eb69..db01e9c 100644
--- a/internal/ui/chat/model.go
+++ b/internal/ui/chat/model.go
@@ -23,6 +23,7 @@ import (
 	"github.com/ayn2op/discordo/internal/ui/chat/channelspicker"
 	"github.com/ayn2op/discordo/internal/ui/chat/commandslist"
 	"github.com/ayn2op/discordo/internal/ui/chat/composer"
+	"github.com/ayn2op/discordo/internal/ui/chat/emojipicker"
 	"github.com/ayn2op/discordo/internal/ui/chat/emojislist"
 	"github.com/ayn2op/discordo/internal/ui/chat/guildstree"
 	"github.com/ayn2op/discordo/internal/ui/chat/memberstree"
@@ -54,9 +55,11 @@ type Model struct {
 	membersTree    memberstree.Model
 	messagesList   messageslist.Model
 	composer       composer.Model
-	channelsPicker channelspicker.Model
+	channelsPicker    channelspicker.Model
 	// attachmentsPicker picks an attachment or link of the selected message.
 	attachmentsPicker attachmentspicker.Model
+	emojiPicker       emojipicker.Model
+	reactingMessage   *discord.Message
 
 	selectedChannel *discord.Channel
 	// windowUnfocused reports whether the terminal window lost focus.
@@ -112,6 +115,7 @@ func NewModel(cfg *config.Config, token string) Model {
 	m.composer = composer.NewModel(cfg, m.state)
 	m.channelsPicker = channelspicker.NewModel(cfg)
 	m.attachmentsPicker = attachmentspicker.NewModel(cfg)
+	m.emojiPicker = emojipicker.NewModel(cfg)
 
 	m.guildsTreeVisible = cfg.Sidebar.Visible
 	m.membersTreeVisible = cfg.MembersTree.Visible
@@ -131,6 +135,7 @@ const (
 	overlayNone overlay = iota
 	overlayChannelsPicker
 	overlayAttachmentsPicker
+	overlayEmojiPicker
 )
 
 // pickerView returns the view of the picker shown on top, or nil if none is open.
@@ -140,6 +145,8 @@ func (m Model) pickerView() tview.Widget {
 		return m.channelsPicker.View()
 	case overlayAttachmentsPicker:
 		return m.attachmentsPicker.View()
+	case overlayEmojiPicker:
+		return m.emojiPicker.View()
 	default:
 		return nil
 	}
@@ -245,6 +252,54 @@ func (m Model) Update(msg tview.Msg) (Model, tview.Cmd) {
 		m.attachmentsPicker.SetItems(picker.Items(msg))
 		m.overlay = overlayAttachmentsPicker
 		return m, nil
+	case messageslist.ReactMsg:
+		m.overlay = overlayEmojiPicker
+		m.reactingMessage = &msg.Message
+		var gID discord.GuildID
+		if m.selectedChannel != nil {
+			gID = m.selectedChannel.GuildID
+		}
+		m.emojiPicker.RefreshEmojis(m.state, gID)
+		return m, nil
+	case emojipicker.CancelMsg:
+		m.overlay = overlayNone
+		m.reactingMessage = nil
+		return m, nil
+	case emojipicker.SelectedMsg:
+		m.overlay = overlayNone
+		if m.reactingMessage == nil || m.selectedChannel == nil {
+			return m, nil
+		}
+		chID := m.selectedChannel.ID
+		msgID := m.reactingMessage.ID
+		targetEmoji := msg.Emoji
+		reactions := m.reactingMessage.Reactions
+		m.reactingMessage = nil
+
+		alreadyReacted := false
+		for _, r := range reactions {
+			if r.Emoji.APIString() == targetEmoji && r.Me {
+				alreadyReacted = true
+				break
+			}
+		}
+
+		return m, func() tview.Msg {
+			if m.state == nil || m.state.Client == nil {
+				return nil
+			}
+			client := m.state.Client
+			if alreadyReacted {
+				if err := client.Unreact(chID, msgID, targetEmoji); err != nil {
+					slog.Error("failed to remove reaction", "channel_id", chID, "message_id", msgID, "emoji", targetEmoji, "err", err)
+				}
+			} else {
+				if err := client.React(chID, msgID, targetEmoji); err != nil {
+					slog.Error("failed to add reaction", "channel_id", chID, "message_id", msgID, "emoji", targetEmoji, "err", err)
+				}
+			}
+			return nil
+		}
 	case messageslist.ReplyMsg:
 		m.composer.StartReply(msg.Message, msg.Name, msg.Mention)
 		m.setFocus(paneComposer)
@@ -328,6 +383,8 @@ func (m *Model) route(msg tview.Msg) tview.Cmd {
 		m.channelsPicker, cmd = m.channelsPicker.Update(msg)
 	case overlayAttachmentsPicker:
 		m.attachmentsPicker, cmd = m.attachmentsPicker.Update(msg)
+	case overlayEmojiPicker:
+		m.emojiPicker, cmd = m.emojiPicker.Update(msg)
 	default:
 		cmd = m.updatePane(m.focused, msg)
 	}
diff --git a/internal/ui/chat/model_test.go b/internal/ui/chat/model_test.go
index 3f9bcb8..4db1c5d 100644
--- a/internal/ui/chat/model_test.go
+++ b/internal/ui/chat/model_test.go
@@ -8,6 +8,8 @@ import (
 	"github.com/ayn2op/arikawa/v3/discord"
 	"github.com/ayn2op/arikawa/v3/gateway"
 	"github.com/ayn2op/discordo/internal/config"
+	"github.com/ayn2op/discordo/internal/ui/chat/emojipicker"
+	"github.com/ayn2op/discordo/internal/ui/chat/messageslist"
 	"github.com/ayn2op/tview"
 	"github.com/gdamore/tcell/v3"
 )
@@ -99,3 +101,35 @@ func TestModelCycleFocus(t *testing.T) {
 		}
 	}
 }
+
+func TestModelReactions(t *testing.T) {
+	m := newTestModel(t)
+	channel := discord.Channel{ID: 1, GuildID: 2, Type: discord.GuildText}
+	m.setSelectedChannel(&channel)
+
+	msg := discord.Message{ID: 10, ChannelID: 1}
+	*m, _ = m.Update(messageslist.ReactMsg{Message: msg})
+	if m.overlay != overlayEmojiPicker {
+		t.Fatalf("overlay = %v, want overlayEmojiPicker", m.overlay)
+	}
+	if m.reactingMessage == nil || m.reactingMessage.ID != 10 {
+		t.Fatalf("reactingMessage = %v, want ID 10", m.reactingMessage)
+	}
+
+	// Cancel closes overlay
+	*m, _ = m.Update(emojipicker.CancelMsg{})
+	if m.overlay != overlayNone {
+		t.Fatalf("overlay after cancel = %v, want overlayNone", m.overlay)
+	}
+
+	// Select triggers react command and closes overlay
+	*m, _ = m.Update(messageslist.ReactMsg{Message: msg})
+	var cmd tview.Cmd
+	*m, cmd = m.Update(emojipicker.SelectedMsg{Emoji: discord.APIEmoji("😄")})
+	if m.overlay != overlayNone {
+		t.Fatalf("overlay after select = %v, want overlayNone", m.overlay)
+	}
+	if cmd == nil {
+		t.Fatal("expected non-nil command for reaction action")
+	}
+}