diff --git a/.gitignore b/.gitignore
index cdf405b6c..68aa74947 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,7 @@
 /.cache
 /.gdbinit
 /.python-version
+/.pyodide-xbuildenv-*
 /Mathics.egg-info
 /Mathics3.egg-info
 ChangeLog
diff --git a/test/builtin/files_io/test_files.py b/test/builtin/files_io/test_files.py
index 7042a728b..c4cd469dd 100644
--- a/test/builtin/files_io/test_files.py
+++ b/test/builtin/files_io/test_files.py
@@ -99,6 +99,10 @@ def test_close():
     ), f"temporary filename {temp_filename} should not appear"
 
 
+@pytest.mark.skipif(
+    sys.platform in ("emscripten",),
+    reason="Pyodide has restricted filesystem access",
+)
 @pytest.mark.parametrize(
     ("str_expr", "msgs", "str_expected", "fail_msg"),
     [
diff --git a/test/builtin/test_datentime.py b/test/builtin/test_datentime.py
index 0fc894483..01583ecfd 100644
--- a/test/builtin/test_datentime.py
+++ b/test/builtin/test_datentime.py
@@ -11,7 +11,7 @@
 
 
 @pytest.mark.skipif(
-    sys.platform in ("win32",) or hasattr(sys, "pyston_version_info"),
+    sys.platform in ("win32", "emscripten") or hasattr(sys, "pyston_version_info"),
     reason="TimeConstrained needs to be rewritten",
 )
 def test_timeremaining():
diff --git a/test/test_main.py b/test/test_main.py
index 982e593e1..dd5671e2b 100644
--- a/test/test_main.py
+++ b/test/test_main.py
@@ -2,6 +2,9 @@
 import os.path as osp
 import re
 import subprocess
+import sys
+
+import pytest
 
 
 def get_testdir():
@@ -9,6 +12,10 @@ def get_testdir():
     return osp.realpath(filename)
 
 
+@pytest.mark.skipif(
+    sys.platform in ("emscripten",),
+    reason="Pyodide does not support processes",
+)
 def test_cli():
     script_file = osp.join(get_testdir(), "data", "script.m")
 
diff --git a/test/test_returncode.py b/test/test_returncode.py
index a1eb67dc8..1e1d11abb 100644
--- a/test/test_returncode.py
+++ b/test/test_returncode.py
@@ -1,6 +1,9 @@
 # -*- coding: utf-8 -*-
 import os.path as osp
 import subprocess
+import sys
+
+import pytest
 
 
 def get_testdir():
@@ -8,6 +11,10 @@ def get_testdir():
     return osp.realpath(filename)
 
 
+@pytest.mark.skipif(
+    sys.platform in ("emscripten",),
+    reason="Pyodide does not support processes",
+)
 def test_returncode():
     assert subprocess.run(["mathics", "-e", "Quit[5]"]).returncode == 5
     assert subprocess.run(["mathics", "-e", "1 + 2'"]).returncode == 0