diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 2fb301156d..287ff923c6 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -39,6 +39,13 @@ var (
 		Channel:  "stable",
 	}
 
+	// LoginNotification configuration for sign-in alerts
+	LoginNotification = struct {
+		Enabled bool
+	}{
+		Enabled: true,
+	}
+
 	// IsInTesting indicates whether the testing is running (unit test or integration test). It can be used for:
 	// * Skip nonsense error logs during testing caused by unreliable code (TODO: this is only a temporary solution, we should make the test code more reliable)
 	// * Panic in dev or testing mode to make the problem more obvious and easier to debug
@@ -171,6 +178,7 @@ func loadCommonSettingsFrom(cfg ConfigProvider) error {
 	loadOtherFrom(cfg)
 	loadUpdateCheckerFrom(cfg)
 	loadNtfyFrom(cfg)
+	loadLoginNotificationFrom(cfg)
 	return nil
 }
 
@@ -181,6 +189,11 @@ func loadUpdateCheckerFrom(cfg ConfigProvider) {
 	UpdateChecker.Channel = sec.Key("CHANNEL").MustString(UpdateChecker.Channel)
 }
 
+func loadLoginNotificationFrom(cfg ConfigProvider) {
+	sec := cfg.Section("login_notification")
+	LoginNotification.Enabled = sec.Key("ENABLED").MustBool(true)
+}
+
 func loadRunModeFrom(rootCfg ConfigProvider) {
 	rootSec := rootCfg.Section("")
 	RunUser = rootSec.Key("RUN_USER").MustString(user.CurrentUsername())
diff --git a/routers/web/auth/auth.go b/routers/web/auth/auth.go
index 9cb0e566fb..0eb4e55107 100644
--- a/routers/web/auth/auth.go
+++ b/routers/web/auth/auth.go
@@ -440,6 +440,9 @@ func handleSignInFull(ctx *context.Context, u *user_model.User, remember bool) {
 		ctx.ServerError("UpdateUser", err)
 		return
 	}
+
+	// Send login notification (email + ntfy)
+	go mailer.SendLoginNotification(u, ctx.RemoteAddr(), ctx.Req.UserAgent())
 }
 
 // extractUserNameFromOAuth2 tries to extract a normalized username from the given OAuth2 user.
diff --git a/services/mailer/mail_login.go b/services/mailer/mail_login.go
new file mode 100644
index 0000000000..62b956514c
--- /dev/null
+++ b/services/mailer/mail_login.go
@@ -0,0 +1,84 @@
+// Copyright 2026 Moko Consulting <hello@mokoconsulting.tech>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package mailer
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	user_model "git.mokoconsulting.tech/MokoConsulting/MokoGitea/models/user"
+	"git.mokoconsulting.tech/MokoConsulting/MokoGitea/modules/log"
+	"git.mokoconsulting.tech/MokoConsulting/MokoGitea/modules/setting"
+	sender_service "git.mokoconsulting.tech/MokoConsulting/MokoGitea/services/mailer/sender"
+)
+
+// SendLoginNotification sends email and ntfy notifications when a user signs in.
+func SendLoginNotification(u *user_model.User, ip, userAgent string) {
+	if !setting.LoginNotification.Enabled {
+		return
+	}
+
+	timestamp := time.Now().UTC().Format("2006-01-02 15:04:05 UTC")
+	subject := fmt.Sprintf("[%s] New sign-in: %s", setting.AppName, u.Name)
+
+	body := fmt.Sprintf(`New sign-in detected
+
+Account:    %s (%s)
+IP Address: %s
+Browser:    %s
+Time:       %s
+Instance:   %s
+
+If this wasn't you, change your password immediately and review your active sessions.
+
+— %s`, u.Name, u.Email, ip, userAgent, timestamp, setting.AppURL, setting.AppName)
+
+	// Email notification
+	if setting.MailService != nil && u.Email != "" {
+		msg := sender_service.NewMessage(u.EmailTo(), subject, body)
+		msg.Info = fmt.Sprintf("Login notification for %s", u.Name)
+		SendAsync(msg)
+		log.Debug("Login notification email sent to %s", u.Email)
+	}
+
+	// ntfy push notification
+	if setting.Ntfy.Enabled && setting.Ntfy.ServerURL != "" {
+		go sendLoginNtfy(subject, u.Name, ip, timestamp)
+	}
+}
+
+func sendLoginNtfy(title, username, ip, timestamp string) {
+	body := fmt.Sprintf("User: %s\nIP: %s\nTime: %s", username, ip, timestamp)
+	url := fmt.Sprintf("%s/%s", setting.Ntfy.ServerURL, setting.Ntfy.DefaultTopic)
+
+	req, err := http.NewRequest("POST", url, bytes.NewBufferString(body))
+	if err != nil {
+		log.Error("ntfy login: create request: %v", err)
+		return
+	}
+
+	req.Header.Set("Title", title)
+	req.Header.Set("Priority", "default")
+	req.Header.Set("Tags", "key,login")
+	req.Header.Set("Click", setting.AppURL+"-/admin")
+	if setting.Ntfy.Token != "" {
+		req.Header.Set("Authorization", "Bearer "+setting.Ntfy.Token)
+	}
+
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		log.Error("ntfy login: send: %v", err)
+		return
+	}
+	defer resp.Body.Close()
+	io.Copy(io.Discard, resp.Body)
+
+	if resp.StatusCode >= 300 {
+		log.Error("ntfy login: status %d", resp.StatusCode)
+	}
+}