diff --git a/edbob/exceptions.py b/edbob/exceptions.py
index a5a802e..58da82f 100644
--- a/edbob/exceptions.py
+++ b/edbob/exceptions.py
@@ -73,6 +73,12 @@ class LoadSpecError(Exception):
         return None
 
 
+class InvalidSpec(LoadSpecError):
+
+    def specifics(self):
+        return "invalid spec"
+
+
 class ModuleMissingAttribute(LoadSpecError):
     """
     Raised during :func:`edbob.load_spec()` when the module imported okay but
diff --git a/edbob/modules.py b/edbob/modules.py
index e3d4287..2cdf59b 100644
--- a/edbob/modules.py
+++ b/edbob/modules.py
@@ -82,6 +82,9 @@ def load_spec(spec):
     necessary.
     """
 
+    if spec.count(':') != 1:
+        raise exceptions.InvalidSpec(spec)
+
     module_path, obj = spec.split(':')
     module = import_module_path(module_path)
     try: