diff --git a/pygmt/helpers/utils.py b/pygmt/helpers/utils.py
index 79b65fc0048..a72dcd6bb51 100644
--- a/pygmt/helpers/utils.py
+++ b/pygmt/helpers/utils.py
@@ -127,7 +127,11 @@ def build_arg_string(kwargs):
     Examples
     --------
 
-    >>> print(build_arg_string(dict(R="1/2/3/4", J="X4i", P="", E=200)))
+    >>> print(
+    ...     build_arg_string(
+    ...         dict(R="1/2/3/4", J="X4i", P="", E=200, X=None, Y=None)
+    ...     )
+    ... )
     -E200 -JX4i -P -R1/2/3/4
     >>> print(
     ...     build_arg_string(
@@ -147,6 +151,8 @@ def build_arg_string(kwargs):
         if is_nonstr_iter(kwargs[key]):
             for value in kwargs[key]:
                 sorted_args.append("-{}{}".format(key, value))
+        elif kwargs[key] is None:  # arguments like -XNone are invalid
+            continue
         else:
             sorted_args.append("-{}{}".format(key, kwargs[key]))