diff --git a/internal/app/app.go b/internal/app/app.go
index 847dd2d..a813014 100644
--- a/internal/app/app.go
+++ b/internal/app/app.go
@@ -21,6 +21,7 @@ type App struct {
 	TagService          *service.TagService
 	ShoppingListService *service.ShoppingListService
 	ExpenseService      *service.ExpenseService
+	InviteService       *service.InviteService
 }
 
 func New(cfg *config.Config) (*App, error) {
@@ -45,6 +46,7 @@ func New(cfg *config.Config) (*App, error) {
 	shoppingListRepository := repository.NewShoppingListRepository(database)
 	listItemRepository := repository.NewListItemRepository(database)
 	expenseRepository := repository.NewExpenseRepository(database)
+	invitationRepository := repository.NewInvitationRepository(database)
 
 	// Services
 	userService := service.NewUserService(userRepository)
@@ -71,6 +73,7 @@ func New(cfg *config.Config) (*App, error) {
 	tagService := service.NewTagService(tagRepository)
 	shoppingListService := service.NewShoppingListService(shoppingListRepository, listItemRepository)
 	expenseService := service.NewExpenseService(expenseRepository)
+	inviteService := service.NewInviteService(invitationRepository, spaceRepository, userRepository, emailService)
 
 	return &App{
 		Cfg:                 cfg,
@@ -83,6 +86,7 @@ func New(cfg *config.Config) (*App, error) {
 		TagService:          tagService,
 		ShoppingListService: shoppingListService,
 		ExpenseService:      expenseService,
+		InviteService:       inviteService,
 	}, nil
 }
 func (a *App) Close() error {
diff --git a/internal/db/migrations/00008_create_space_invitations_table.sql b/internal/db/migrations/00008_create_space_invitations_table.sql
new file mode 100644
index 0000000..6521cb1
--- /dev/null
+++ b/internal/db/migrations/00008_create_space_invitations_table.sql
@@ -0,0 +1,25 @@
+-- +goose Up
+-- +goose StatementBegin
+CREATE TABLE IF NOT EXISTS space_invitations (
+    token TEXT PRIMARY KEY NOT NULL,
+    space_id TEXT NOT NULL,
+    inviter_id TEXT NOT NULL,
+    email TEXT NOT NULL,
+    status TEXT NOT NULL CHECK (status IN ('pending', 'accepted', 'expired')),
+    expires_at TIMESTAMP NOT NULL,
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    FOREIGN KEY (space_id) REFERENCES spaces(id) ON DELETE CASCADE,
+    FOREIGN KEY (inviter_id) REFERENCES users(id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_space_invitations_email ON space_invitations(email);
+CREATE INDEX IF NOT EXISTS idx_space_invitations_space_id ON space_invitations(space_id);
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+DROP INDEX IF EXISTS idx_space_invitations_space_id;
+DROP INDEX IF EXISTS idx_space_invitations_email;
+DROP TABLE IF EXISTS space_invitations;
+-- +goose StatementEnd
diff --git a/internal/handler/auth.go b/internal/handler/auth.go
index 67b8d74..a994ea8 100644
--- a/internal/handler/auth.go
+++ b/internal/handler/auth.go
@@ -15,11 +15,12 @@ import (
 )
 
 type authHandler struct {
-	authService *service.AuthService
+	authService   *service.AuthService
+	inviteService *service.InviteService
 }
 
-func NewAuthHandler(authService *service.AuthService) *authHandler {
-	return &authHandler{authService: authService}
+func NewAuthHandler(authService *service.AuthService, inviteService *service.InviteService) *authHandler {
+	return &authHandler{authService: authService, inviteService: inviteService}
 }
 
 func (h *authHandler) AuthPage(w http.ResponseWriter, r *http.Request) {
@@ -88,6 +89,28 @@ func (h *authHandler) VerifyMagicLink(w http.ResponseWriter, r *http.Request) {
 
 	h.authService.SetJWTCookie(w, jwtToken, time.Now().Add(7*24*time.Hour))
 
+	// Check for pending invite
+	inviteCookie, err := r.Cookie("pending_invite")
+	if err == nil && inviteCookie.Value != "" {
+		spaceID, err := h.inviteService.AcceptInvite(inviteCookie.Value, user.ID)
+		if err != nil {
+			slog.Error("failed to process pending invite", "error", err, "token", inviteCookie.Value)
+			// Don't fail the login, just maybe notify user?
+		} else {
+			slog.Info("accepted pending invite", "user_id", user.ID, "space_id", spaceID)
+			// Clear cookie
+			http.SetCookie(w, &http.Cookie{
+				Name:     "pending_invite",
+				Value:    "",
+				Path:     "/",
+				MaxAge:   -1,
+				HttpOnly: true,
+			})
+			// If we want to redirect to the space immediately, we can.
+			// But check onboarding first.
+		}
+	}
+
 	needsOnboarding, err := h.authService.NeedsOnboarding(user.ID)
 	if err != nil {
 		slog.Warn("failed to check onboarding status", "error", err, "user_id", user.ID)
diff --git a/internal/handler/space.go b/internal/handler/space.go
index 5d6a4ec..06260b9 100644
--- a/internal/handler/space.go
+++ b/internal/handler/space.go
@@ -20,14 +20,16 @@ type SpaceHandler struct {
 	tagService     *service.TagService
 	listService    *service.ShoppingListService
 	expenseService *service.ExpenseService
+	inviteService  *service.InviteService
 }
 
-func NewSpaceHandler(ss *service.SpaceService, ts *service.TagService, sls *service.ShoppingListService, es *service.ExpenseService) *SpaceHandler {
+func NewSpaceHandler(ss *service.SpaceService, ts *service.TagService, sls *service.ShoppingListService, es *service.ExpenseService, is *service.InviteService) *SpaceHandler {
 	return &SpaceHandler{
 		spaceService:   ss,
 		tagService:     ts,
 		listService:    sls,
 		expenseService: es,
+		inviteService:  is,
 	}
 }
 
@@ -353,3 +355,57 @@ func (h *SpaceHandler) CreateExpense(w http.ResponseWriter, r *http.Request) {
 
 	ui.Render(w, r, pages.ExpenseCreatedResponse(newExpense, balance))
 }
+
+func (h *SpaceHandler) CreateInvite(w http.ResponseWriter, r *http.Request) {
+	spaceID := r.PathValue("spaceID")
+	user := ctxkeys.User(r.Context())
+
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "Bad Request", http.StatusBadRequest)
+		return
+	}
+
+	email := r.FormValue("email")
+	if email == "" {
+		http.Error(w, "Email is required", http.StatusBadRequest)
+		return
+	}
+
+	_, err := h.inviteService.CreateInvite(spaceID, user.ID, email)
+	if err != nil {
+		slog.Error("failed to create invite", "error", err, "space_id", spaceID)
+		http.Error(w, "Failed to create invite", http.StatusInternalServerError)
+		return
+	}
+
+	// TODO: Return a nice UI response (toast or list update)
+	w.Write([]byte("Invitation sent!"))
+}
+
+func (h *SpaceHandler) JoinSpace(w http.ResponseWriter, r *http.Request) {
+	token := r.PathValue("token")
+	user := ctxkeys.User(r.Context())
+
+	if user != nil {
+		spaceID, err := h.inviteService.AcceptInvite(token, user.ID)
+		if err != nil {
+			slog.Error("failed to accept invite", "error", err, "token", token)
+			http.Error(w, "Failed to join space: "+err.Error(), http.StatusBadRequest)
+			return
+		}
+
+		http.Redirect(w, r, "/app/spaces/"+spaceID, http.StatusSeeOther)
+		return
+	}
+
+	// Not logged in: set cookie and redirect to auth
+	http.SetCookie(w, &http.Cookie{
+		Name:     "pending_invite",
+		Value:    token,
+		Path:     "/",
+		Expires:  time.Now().Add(1 * time.Hour),
+		HttpOnly: true,
+		SameSite: http.SameSiteLaxMode,
+	})
+	http.Redirect(w, r, "/auth?invite=true", http.StatusTemporaryRedirect)
+}
diff --git a/internal/model/invitation.go b/internal/model/invitation.go
new file mode 100644
index 0000000..09b5069
--- /dev/null
+++ b/internal/model/invitation.go
@@ -0,0 +1,22 @@
+package model
+
+import "time"
+
+type InvitationStatus string
+
+const (
+	InvitationStatusPending  InvitationStatus = "pending"
+	InvitationStatusAccepted InvitationStatus = "accepted"
+	InvitationStatusExpired  InvitationStatus = "expired"
+)
+
+type SpaceInvitation struct {
+	Token     string           `db:"token"`
+	SpaceID   string           `db:"space_id"`
+	InviterID string           `db:"inviter_id"`
+	Email     string           `db:"email"`
+	Status    InvitationStatus `db:"status"`
+	ExpiresAt time.Time        `db:"expires_at"`
+	CreatedAt time.Time        `db:"created_at"`
+	UpdatedAt time.Time        `db:"updated_at"`
+}
diff --git a/internal/repository/invitation.go b/internal/repository/invitation.go
new file mode 100644
index 0000000..37c2085
--- /dev/null
+++ b/internal/repository/invitation.go
@@ -0,0 +1,67 @@
+package repository
+
+import (
+	"database/sql"
+	"errors"
+
+	"git.juancwu.dev/juancwu/budgit/internal/model"
+	"github.com/jmoiron/sqlx"
+)
+
+var (
+	ErrInvitationNotFound = errors.New("invitation not found")
+)
+
+type InvitationRepository interface {
+	Create(invitation *model.SpaceInvitation) error
+	GetByToken(token string) (*model.SpaceInvitation, error)
+	GetBySpaceID(spaceID string) ([]*model.SpaceInvitation, error)
+	UpdateStatus(token string, status model.InvitationStatus) error
+	Delete(token string) error
+}
+
+type invitationRepository struct {
+	db *sqlx.DB
+}
+
+func NewInvitationRepository(db *sqlx.DB) InvitationRepository {
+	return &invitationRepository{db: db}
+}
+
+func (r *invitationRepository) Create(invitation *model.SpaceInvitation) error {
+	query := `
+		INSERT INTO space_invitations (token, space_id, inviter_id, email, status, expires_at, created_at, updated_at)
+		VALUES (:token, :space_id, :inviter_id, :email, :status, :expires_at, :created_at, :updated_at)
+	`
+	_, err := r.db.NamedExec(query, invitation)
+	return err
+}
+
+func (r *invitationRepository) GetByToken(token string) (*model.SpaceInvitation, error) {
+	var invitation model.SpaceInvitation
+	query := `SELECT * FROM space_invitations WHERE token = $1`
+	err := r.db.Get(&invitation, query, token)
+	if err == sql.ErrNoRows {
+		return nil, ErrInvitationNotFound
+	}
+	return &invitation, err
+}
+
+func (r *invitationRepository) GetBySpaceID(spaceID string) ([]*model.SpaceInvitation, error) {
+	var invitations []*model.SpaceInvitation
+	query := `SELECT * FROM space_invitations WHERE space_id = $1 ORDER BY created_at DESC`
+	err := r.db.Select(&invitations, query, spaceID)
+	return invitations, err
+}
+
+func (r *invitationRepository) UpdateStatus(token string, status model.InvitationStatus) error {
+	query := `UPDATE space_invitations SET status = $1, updated_at = CURRENT_TIMESTAMP WHERE token = $2`
+	_, err := r.db.Exec(query, status, token)
+	return err
+}
+
+func (r *invitationRepository) Delete(token string) error {
+	query := `DELETE FROM space_invitations WHERE token = $1`
+	_, err := r.db.Exec(query, token)
+	return err
+}
diff --git a/internal/routes/routes.go b/internal/routes/routes.go
index 9f99ab6..a1e18d3 100644
--- a/internal/routes/routes.go
+++ b/internal/routes/routes.go
@@ -11,10 +11,10 @@ import (
 )
 
 func SetupRoutes(a *app.App) http.Handler {
-	auth := handler.NewAuthHandler(a.AuthService)
+	auth := handler.NewAuthHandler(a.AuthService, a.InviteService)
 	home := handler.NewHomeHandler()
 	dashboard := handler.NewDashboardHandler()
-	space := handler.NewSpaceHandler(a.SpaceService, a.TagService, a.ShoppingListService, a.ExpenseService)
+	space := handler.NewSpaceHandler(a.SpaceService, a.TagService, a.ShoppingListService, a.ExpenseService, a.InviteService)
 
 	mux := http.NewServeMux()
 
@@ -103,6 +103,13 @@ func SetupRoutes(a *app.App) http.Handler {
 	createExpenseWithAccess := middleware.RequireSpaceAccess(a.SpaceService)(createExpenseHandler)
 	mux.Handle("POST /app/spaces/{spaceID}/expenses", createExpenseWithAccess)
 
+	// Invite routes
+	createInviteHandler := middleware.RequireAuth(space.CreateInvite)
+	createInviteWithAccess := middleware.RequireSpaceAccess(a.SpaceService)(createInviteHandler)
+	mux.Handle("POST /app/spaces/{spaceID}/invites", createInviteWithAccess)
+
+	mux.HandleFunc("GET /join/{token}", space.JoinSpace)
+
 	// 404
 	mux.HandleFunc("/{path...}", home.NotFoundPage)
 
diff --git a/internal/service/email.go b/internal/service/email.go
index cf3438c..a482f69 100644
--- a/internal/service/email.go
+++ b/internal/service/email.go
@@ -201,6 +201,29 @@ func (s *EmailService) SendWelcomeEmail(email, name string) error {
 	return err
 }
 
+func (s *EmailService) SendInvitationEmail(email, spaceName, inviterName, token string) error {
+	inviteURL := fmt.Sprintf("%s/join/%s", s.appURL, token)
+	subject, body := invitationEmailTemplate(spaceName, inviterName, inviteURL, s.appName)
+
+	if !s.isProd {
+		slog.Info("email sent (dev mode)", "type", "invitation", "to", email, "subject", subject, "url", inviteURL)
+		return nil
+	}
+
+	params := &EmailParams{
+		From:    s.fromEmail,
+		To:      []string{email},
+		Subject: subject,
+		Text:    body,
+	}
+
+	_, err := s.client.SendWithContext(context.Background(), params)
+	if err == nil {
+		slog.Info("email sent", "type", "invitation", "to", email)
+	}
+	return err
+}
+
 func magicLinkEmailTemplate(magicURL, appName string) (string, string) {
 	subject := fmt.Sprintf("Sign in to %s", appName)
 	body := fmt.Sprintf(`Click this link to sign in to your account:
@@ -231,3 +254,20 @@ The %s Team`, name, dashboardURL, appName)
 
 	return subject, body
 }
+
+func invitationEmailTemplate(spaceName, inviterName, inviteURL, appName string) (string, string) {
+	subject := fmt.Sprintf("%s invited you to join %s on %s", inviterName, spaceName, appName)
+	body := fmt.Sprintf(`Hi,
+
+%s has invited you to join the space "%s" on %s.
+
+Click the link below to accept the invitation:
+%s
+
+If you don't have an account, you will be asked to create one.
+
+Best,
+The %s Team`, inviterName, spaceName, appName, inviteURL, appName)
+
+	return subject, body
+}
diff --git a/internal/service/invite.go b/internal/service/invite.go
new file mode 100644
index 0000000..d12d040
--- /dev/null
+++ b/internal/service/invite.go
@@ -0,0 +1,112 @@
+package service
+
+import (
+	"errors"
+	"time"
+
+	"git.juancwu.dev/juancwu/budgit/internal/model"
+	"git.juancwu.dev/juancwu/budgit/internal/repository"
+	"git.juancwu.dev/juancwu/budgit/internal/utils"
+)
+
+type InviteService struct {
+	inviteRepo repository.InvitationRepository
+	spaceRepo  repository.SpaceRepository
+	userRepo   repository.UserRepository
+	emailSvc   *EmailService
+}
+
+func NewInviteService(ir repository.InvitationRepository, sr repository.SpaceRepository, ur repository.UserRepository, es *EmailService) *InviteService {
+	return &InviteService{
+		inviteRepo: ir,
+		spaceRepo:  sr,
+		userRepo:   ur,
+		emailSvc:   es,
+	}
+}
+
+func (s *InviteService) CreateInvite(spaceID, inviterID, email string) (*model.SpaceInvitation, error) {
+	// Check if space exists
+	space, err := s.spaceRepo.ByID(spaceID)
+	if err != nil {
+		return nil, err
+	}
+
+	// Check if inviter is member/owner of space? (Ideally yes, but for now assuming caller checks permissions)
+
+	// Check if user is already a member
+	// This would require a method on SpaceRepo or SpaceService.
+	// For now, let's proceed.
+
+	token := utils.RandomID() // Or a more secure token generator
+	expiresAt := time.Now().Add(48 * time.Hour)
+
+	invitation := &model.SpaceInvitation{
+		Token:     token,
+		SpaceID:   spaceID,
+		InviterID: inviterID,
+		Email:     email,
+		Status:    model.InvitationStatusPending,
+		ExpiresAt: expiresAt,
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+	}
+
+	if err := s.inviteRepo.Create(invitation); err != nil {
+		return nil, err
+	}
+
+	// Get inviter name
+	inviter, err := s.userRepo.ByID(inviterID)
+	inviterName := "Someone"
+	if err == nil {
+		inviterName = inviter.Email // Or Name if available
+		// Get profile for better name?
+	}
+
+	// Send Email
+	go s.emailSvc.SendInvitationEmail(email, space.Name, inviterName, token)
+
+	return invitation, nil
+}
+
+func (s *InviteService) AcceptInvite(token, userID string) (string, error) {
+	invite, err := s.inviteRepo.GetByToken(token)
+	if err != nil {
+		return "", err
+	}
+
+	if invite.Status != model.InvitationStatusPending {
+		return "", errors.New("invitation is not pending")
+	}
+
+	if time.Now().After(invite.ExpiresAt) {
+		s.inviteRepo.UpdateStatus(token, model.InvitationStatusExpired)
+		return "", errors.New("invitation expired")
+	}
+
+	// Add user to space
+	err = s.spaceRepo.AddMember(invite.SpaceID, userID, model.RoleMember)
+	if err != nil {
+		return "", err
+	}
+
+	return invite.SpaceID, s.inviteRepo.UpdateStatus(token, model.InvitationStatusAccepted)
+}
+
+func (s *InviteService) GetPendingInvites(spaceID string) ([]*model.SpaceInvitation, error) {
+	// Filter for pending only in memory or repo?
+	// Repo returns all.
+	all, err := s.inviteRepo.GetBySpaceID(spaceID)
+	if err != nil {
+		return nil, err
+	}
+
+	var pending []*model.SpaceInvitation
+	for _, inv := range all {
+		if inv.Status == model.InvitationStatusPending {
+			pending = append(pending, inv)
+		}
+	}
+	return pending, nil
+}
diff --git a/internal/ui/pages/app_space_dashboard.templ b/internal/ui/pages/app_space_dashboard.templ
index 4ecab88..e7b65cf 100644
--- a/internal/ui/pages/app_space_dashboard.templ
+++ b/internal/ui/pages/app_space_dashboard.templ
@@ -2,13 +2,56 @@ package pages
 
 import (
 	"git.juancwu.dev/juancwu/budgit/internal/model"
+	"git.juancwu.dev/juancwu/budgit/internal/ui/components/button"
+	"git.juancwu.dev/juancwu/budgit/internal/ui/components/csrf"
+	"git.juancwu.dev/juancwu/budgit/internal/ui/components/dialog"
+	"git.juancwu.dev/juancwu/budgit/internal/ui/components/input"
 	"git.juancwu.dev/juancwu/budgit/internal/ui/layouts"
 )
 
 templ SpaceDashboardPage(space *model.Space, lists []*model.ShoppingList, tags []*model.Tag) {
 	@layouts.Space("Dashboard", space) {
 		<div class="space-y-4">
-			<h1 class="text-2xl font-bold">Welcome to { space.Name }!</h1>
+			<div class="flex justify-between items-center">
+				<h1 class="text-2xl font-bold">Welcome to { space.Name }!</h1>
+				@dialog.Dialog(dialog.Props{ ID: "invite-member-dialog" }) {
+					@dialog.Trigger() {
+						@button.Button() {
+							Invite Member
+						}
+					}
+					@dialog.Content() {
+						@dialog.Header() {
+							@dialog.Title() { Invite Member }
+							@dialog.Description() {
+								Send an invitation email to add a new member to this space.
+							}
+						}
+						<form
+							hx-post={ "/app/spaces/" + space.ID + "/invites" }
+							hx-swap="innerHTML"
+							class="space-y-4"
+						>
+							@csrf.Token()
+							<div>
+								<label for="email" class="label">Email Address</label>
+								@input.Input(input.Props{
+									Name: "email",
+									ID: "email",
+									Type: "email",
+									Attributes: templ.Attributes{"required": "true"},
+								})
+							</div>
+							<div class="flex justify-end">
+								@button.Button(button.Props{ Type: button.TypeSubmit }) {
+									Send Invitation
+								}
+							</div>
+						</form>
+					}
+				}
+			</div>
+
 			<div class="grid grid-cols-1 md:grid-cols-2 gap-4">
 				// Shopping Lists section
 				<div class="border rounded-lg p-4">
@@ -39,4 +82,4 @@ templ SpaceDashboardPage(space *model.Space, lists []*model.ShoppingList, tags [
 			</div>
 		</div>
 	}
-}
+}
\ No newline at end of file