diff --git a/style/fontspec.el b/style/fontspec.el
index 144b976..5ec7bb4 100644
--- a/style/fontspec.el
+++ b/style/fontspec.el
@@ -166,6 +166,7 @@ to retrieve the list of fonts."
 (TeX-add-style-hook
  "fontspec"
  (lambda ()
+   (TeX-check-engine-add-engines 'luatex 'xetex)
    (TeX-run-style-hooks "expl3" "xparse")
    (TeX-add-symbols
     ;; Font selection
diff --git a/tex-buf.el b/tex-buf.el
index b5ed365..dc7e3c6 100644
--- a/tex-buf.el
+++ b/tex-buf.el
@@ -332,6 +332,91 @@ This works only with TeX commands and if the
 (defconst TeX-error-overview-buffer-name "*TeX errors*"
   "Name of the buffer in which to show error list.")
 
+(defcustom TeX-check-engine t
+  "Whether AUCTeX should check the correct engine has been set before running LaTeX commands."
+  :group 'TeX-command
+  :type 'boolean)
+
+(defvar TeX-check-engine-list '(default luatex omega xetex)
+  "List of engines required by the loaded TeX packages.
+
+Do not set this variable directly, use
+`TeX-check-engine-add-engines' to specify required engines.")
+(make-variable-buffer-local 'TeX-check-engine-list)
+
+(defun TeX-check-engine-add-engines (&rest engines)
+  "Add ENGINES to list of required engines.
+
+This function calculates the intersection between
+`TeX-check-engine-list' and the list of provided engines.
+
+See for example style/fontspec.el"
+  (let ((list TeX-check-engine-list)
+	(res nil))
+    (setq TeX-check-engine-list
+	  ;; The following is based on the definition of `cl-intersection' of
+	  ;; GNU Emacs.
+	  (and list engines
+	       (if (equal list engines) list
+		 (or (>= (length list) (length engines))
+		     (setq list (prog1 engines (setq engines list))))
+		 (while engines
+		   (if (memq (car engines) list)
+		       (push (car engines) res))
+		   (pop engines))
+		 res)))))
+
+(defun TeX-check-engine ()
+  "Check the correct engine has been set.
+
+Look into `TeX-check-engine-list' for the required engines."
+  (and TeX-check-engine-list
+       (null (memq TeX-engine TeX-check-engine-list))
+       (memq TeX-engine '(default luatex omega xetex))
+       ;; The engine set is not listed in `TeX-check-engine-list'.  We check
+       ;; only builtin engines because we can't take care of custom ones.  Do
+       ;; nothing if there is no allowed engine, we don't know what to do in
+       ;; that case.
+       (let ((length (length TeX-check-engine-list))
+	     (name-alist '((default . "TeX")
+			   (luatex  . "LuaTeX")
+			   (omega   . "Omega")
+			   (xetex   . "XeTeX")))
+	     (completion-ignore-case t)
+	     (engine nil))
+	 (cond
+	  ;; There is exactly one allowed engine.
+	  ((= length 1)
+	   (if (y-or-n-p (format "%s is required to build this document.
+Do you want to use this engine?" (cdr (assoc (car TeX-check-engine-list)
+					     name-alist))))
+	       (setq engine (car TeX-check-engine-list))))
+	  ;; More than one engine is allowed.
+	  ((> length 1)
+	   (if (y-or-n-p (format "%s are required to build this document.
+Do you want to select one of these engines?"
+				 (mapconcat
+				  (lambda (elt) (cdr (assoc elt name-alist)))
+				  TeX-check-engine-list ", ")))
+	       (setq engine
+		     (car (rassoc
+			   (completing-read
+			    (format
+			     "Choose between %s: "
+			     (mapconcat
+			      (lambda (elt) (cdr (assoc elt name-alist)))
+			      TeX-check-engine-list ", "))
+			    (mapcar
+			     (lambda (elt) (cdr (assoc elt name-alist)))
+			     TeX-check-engine-list))
+			   name-alist))))))
+	 (when engine
+	   (TeX-engine-set engine)
+	   (when (and (fboundp 'add-file-local-variable)
+		      (y-or-n-p "Do you want to remember the choice?"))
+	     (add-file-local-variable 'TeX-engine engine)
+	     (save-buffer))))))
+
 (defun TeX-command (name file &optional override-confirm)
   "Run command NAME on the file returned by calling FILE.
 
@@ -343,7 +428,13 @@ Use the information in `TeX-command-list' to determine how to run
 the command.
 
 If OVERRIDE-CONFIRM is a prefix argument, confirmation will be
-asked if it is positive, and suppressed if it is not."
+asked if it is positive, and suppressed if it is not.
+
+When `TeX-check-engine' is non-nil, check the correct engine has
+been set before running LaTeX commands."
+  (and (string= name "LaTeX") TeX-check-engine
+       (TeX-check-engine))
+
   (cond ((eq file 'TeX-region-file)
 	 (setq TeX-current-process-region-p t))
 	((eq file 'TeX-master-file)