diff --git a/src/octoprint/printer/__init__.py b/src/octoprint/printer/__init__.py
index e26a80e4..8e4b1e3c 100644
--- a/src/octoprint/printer/__init__.py
+++ b/src/octoprint/printer/__init__.py
@@ -299,6 +299,7 @@ class PrinterInterface(object):
 		        after the file is selected.
 
 		Raises:
+		    InvalidFileType: if the file is not a machinecode file and hence cannot be printed
 		    InvalidFileLocation: if an absolute path was provided and not contained within local storage or
 		        doesn't exist
 		"""
@@ -593,3 +594,6 @@ class UnknownScript(Exception):
 
 class InvalidFileLocation(Exception):
 	pass
+
+class InvalidFileType(Exception):
+	pass
diff --git a/src/octoprint/printer/standard.py b/src/octoprint/printer/standard.py
index a0c1b817..45c309c7 100644
--- a/src/octoprint/printer/standard.py
+++ b/src/octoprint/printer/standard.py
@@ -17,9 +17,9 @@ import time
 
 from octoprint import util as util
 from octoprint.events import eventManager, Events
-from octoprint.filemanager import FileDestinations, NoSuchStorage
+from octoprint.filemanager import FileDestinations, NoSuchStorage, valid_file_type
 from octoprint.plugin import plugin_manager, ProgressPlugin
-from octoprint.printer import PrinterInterface, PrinterCallback, UnknownScript, InvalidFileLocation
+from octoprint.printer import PrinterInterface, PrinterCallback, UnknownScript, InvalidFileLocation, InvalidFileType
 from octoprint.printer.estimation import TimeEstimationHelper
 from octoprint.settings import settings
 from octoprint.util import comm as comm
@@ -846,6 +846,9 @@ class Printer(PrinterInterface, comm.MachineComPrintCallback):
 		self._stateMonitor.add_temperature(data)
 
 	def _validateJob(self, filename, sd):
+		if not valid_file_type(filename, type="machinecode"):
+			raise InvalidFileType("{} is not a machinecode file, cannot print".format(filename))
+
 		if sd:
 			return