diff --git a/changelog/5017.bugfix.rst b/changelog/5017.bugfix.rst
new file mode 100644
index 00000000000..20a64e70cfc
--- /dev/null
+++ b/changelog/5017.bugfix.rst
@@ -0,0 +1 @@
+``pathlib2`` is no longer used, avoiding a number of problems when mixing ``pathlib2.Path`` and ``pathlib.Path`` objects. pytest now always uses the native ``pathlib`` module.
diff --git a/doc/en/tmpdir.rst b/doc/en/tmpdir.rst
index 01397a5ba2c..d228dd0233a 100644
--- a/doc/en/tmpdir.rst
+++ b/doc/en/tmpdir.rst
@@ -9,13 +9,11 @@ The ``tmp_path`` fixture
 ------------------------
 
 
-
-
 You can use the ``tmp_path`` fixture which will
 provide a temporary directory unique to the test invocation,
 created in the `base temporary directory`_.
 
-``tmp_path`` is a ``pathlib/pathlib2.Path`` object. Here is an example test usage:
+``tmp_path`` is a ``pathlib.Path`` object. Here is an example test usage:
 
 .. code-block:: python
 
diff --git a/setup.py b/setup.py
index 4c87c6429bb..fb110b9fffd 100644
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,6 @@
     "attrs>=17.4.0",
     "more-itertools>=4.0.0",
     "atomicwrites>=1.0",
-    'pathlib2>=2.2.0;python_version<"3.6"',
     'colorama;sys_platform=="win32"',
     "pluggy>=0.12,<1.0",
     "importlib-metadata>=0.12",
diff --git a/src/_pytest/cacheprovider.py b/src/_pytest/cacheprovider.py
index 17463959fb4..5cfedb51476 100755
--- a/src/_pytest/cacheprovider.py
+++ b/src/_pytest/cacheprovider.py
@@ -50,7 +50,7 @@ def for_config(cls, config):
 
     @staticmethod
     def cache_dir_from_config(config):
-        return resolve_from_str(config.getini("cache_dir"), config.rootdir)
+        return resolve_from_str(config.getini("cache_dir"), str(config.rootdir))
 
     def warn(self, fmt, **args):
         from _pytest.warnings import _issue_warning_captured
@@ -76,7 +76,8 @@ def makedir(self, name):
         if len(name.parts) > 1:
             raise ValueError("name is not allowed to contain path separators")
         res = self._cachedir.joinpath("d", name)
-        res.mkdir(exist_ok=True, parents=True)
+        if not res.is_dir():
+            os.makedirs(str(res))
         return py.path.local(res)
 
     def _getvaluepath(self, key):
@@ -115,7 +116,7 @@ def set(self, key, value):
                 cache_dir_exists_already = True
             else:
                 cache_dir_exists_already = self._cachedir.exists()
-                path.parent.mkdir(exist_ok=True, parents=True)
+                os.makedirs(str(path.parent))
         except (IOError, OSError):
             self.warn("could not create cache path {path}", path=path)
             return
@@ -132,14 +133,17 @@ def set(self, key, value):
     def _ensure_supporting_files(self):
         """Create supporting files in the cache dir that are not really part of the cache."""
         readme_path = self._cachedir / "README.md"
-        readme_path.write_text(README_CONTENT)
+        with readme_path.open("w") as f:
+            f.write(README_CONTENT)
 
         gitignore_path = self._cachedir.joinpath(".gitignore")
         msg = "# Created by pytest automatically.\n*"
-        gitignore_path.write_text(msg, encoding="UTF-8")
+        with gitignore_path.open("w", encoding="UTF-8") as f:
+            f.write(msg)
 
         cachedir_tag_path = self._cachedir.joinpath("CACHEDIR.TAG")
-        cachedir_tag_path.write_bytes(CACHEDIR_TAG_CONTENT)
+        with cachedir_tag_path.open("wb") as f:
+            f.write(CACHEDIR_TAG_CONTENT)
 
 
 class LFPlugin:
@@ -160,7 +164,7 @@ def last_failed_paths(self):
         try:
             return self._last_failed_paths
         except AttributeError:
-            rootpath = Path(self.config.rootdir)
+            rootpath = Path(str(self.config.rootdir))
             result = {rootpath / nodeid.split("::")[0] for nodeid in self.lastfailed}
             result = {x for x in result if x.exists()}
             self._last_failed_paths = result
@@ -174,7 +178,7 @@ def pytest_ignore_collect(self, path):
         if self.active and self.config.getoption("lf") and path.isfile():
             last_failed_paths = self.last_failed_paths()
             if last_failed_paths:
-                skip_it = Path(path) not in self.last_failed_paths()
+                skip_it = Path(str(path)) not in self.last_failed_paths()
                 if skip_it:
                     self._skipped_files += 1
                 return skip_it
@@ -385,7 +389,7 @@ def pytest_report_header(config):
         # starting with .., ../.. if sensible
 
         try:
-            displaypath = cachedir.relative_to(config.rootdir)
+            displaypath = cachedir.relative_to(str(config.rootdir))
         except ValueError:
             displaypath = cachedir
         return "cachedir: {}".format(displaypath)
diff --git a/src/_pytest/pathlib.py b/src/_pytest/pathlib.py
index 3269c25ed7b..7e5a369424c 100644
--- a/src/_pytest/pathlib.py
+++ b/src/_pytest/pathlib.py
@@ -11,14 +11,11 @@
 from os.path import expandvars
 from os.path import isabs
 from os.path import sep
+from pathlib import Path
+from pathlib import PurePath
 from posixpath import sep as posix_sep
 
 
-if sys.version_info[:2] >= (3, 6):
-    from pathlib import Path, PurePath
-else:
-    from pathlib2 import Path, PurePath
-
 __all__ = ["Path", "PurePath"]
 
 
@@ -254,7 +251,6 @@ def make_numbered_dir_with_cleanup(root, prefix, keep, lock_timeout):
 
 
 def resolve_from_str(input, root):
-    assert not isinstance(input, Path), "would break on py2"
     root = Path(root)
     input = expanduser(input)
     input = expandvars(input)
diff --git a/src/_pytest/tmpdir.py b/src/_pytest/tmpdir.py
index f2c4d905cf5..284815cabd0 100644
--- a/src/_pytest/tmpdir.py
+++ b/src/_pytest/tmpdir.py
@@ -66,7 +66,8 @@ def getbasetemp(self):
             # use a sub-directory in the temproot to speed-up
             # make_numbered_dir() call
             rootdir = temproot.joinpath("pytest-of-{}".format(user))
-            rootdir.mkdir(exist_ok=True)
+            if not rootdir.is_dir():
+                os.mkdir(str(rootdir))
             basetemp = make_numbered_dir_with_cleanup(
                 prefix="pytest-", root=rootdir, keep=3, lock_timeout=LOCK_TIMEOUT
             )
@@ -180,10 +181,6 @@ def tmp_path(request, tmp_path_factory):
     created as a sub directory of the base temporary
     directory.  The returned object is a :class:`pathlib.Path`
     object.
-
-    .. note::
-
-        in python < 3.6 this is a pathlib2.Path
     """
 
     return _mk_tmp(request, tmp_path_factory)
diff --git a/testing/test_cacheprovider.py b/testing/test_cacheprovider.py
index a2e701740a0..0989a9c710d 100644
--- a/testing/test_cacheprovider.py
+++ b/testing/test_cacheprovider.py
@@ -27,7 +27,8 @@ def test_config_cache_dataerror(self, testdir):
         cache = config.cache
         pytest.raises(TypeError, lambda: cache.set("key/name", cache))
         config.cache.set("key/name", 0)
-        config.cache._getvaluepath("key/name").write_bytes(b"123invalid")
+        with config.cache._getvaluepath("key/name").open("wb") as f:
+            f.write(b"123invalid")
         val = config.cache.get("key/name", -2)
         assert val == -2
 
@@ -1031,12 +1032,15 @@ def test_gitignore(testdir):
     cache.set("foo", "bar")
     msg = "# Created by pytest automatically.\n*"
     gitignore_path = cache._cachedir.joinpath(".gitignore")
-    assert gitignore_path.read_text(encoding="UTF-8") == msg
+    with gitignore_path.open("r", encoding="UTF-8") as f:
+        assert f.read() == msg
 
     # Does not overwrite existing/custom one.
-    gitignore_path.write_text("custom")
+    with gitignore_path.open("w", encoding="UTF-8") as f:
+        f.write("custom")
     cache.set("something", "else")
-    assert gitignore_path.read_text(encoding="UTF-8") == "custom"
+    with gitignore_path.open("r", encoding="UTF-8") as f:
+        assert f.read() == "custom"
 
 
 def test_does_not_create_boilerplate_in_existing_dirs(testdir):
@@ -1066,4 +1070,5 @@ def test_cachedir_tag(testdir):
     cache = Cache.for_config(config)
     cache.set("foo", "bar")
     cachedir_tag_path = cache._cachedir.joinpath("CACHEDIR.TAG")
-    assert cachedir_tag_path.read_bytes() == CACHEDIR_TAG_CONTENT
+    with cachedir_tag_path.open("rb") as f:
+        assert f.read() == CACHEDIR_TAG_CONTENT
diff --git a/testing/test_reports.py b/testing/test_reports.py
index b8b1a5406d1..786d97e9fee 100644
--- a/testing/test_reports.py
+++ b/testing/test_reports.py
@@ -215,7 +215,7 @@ def test_a():
         assert len(reports) == 3
         test_a_call = reports[1]
         test_a_call.path1 = testdir.tmpdir
-        test_a_call.path2 = Path(testdir.tmpdir)
+        test_a_call.path2 = Path(str(testdir.tmpdir))
         data = test_a_call._to_json()
         assert data["path1"] == str(testdir.tmpdir)
         assert data["path2"] == str(testdir.tmpdir)
diff --git a/testing/test_tmpdir.py b/testing/test_tmpdir.py
index a7c0ed7eaa7..53727137ac3 100644
--- a/testing/test_tmpdir.py
+++ b/testing/test_tmpdir.py
@@ -322,7 +322,8 @@ def test_rmtree(self, tmp_path):
 
         adir.mkdir()
         afile = adir / "afile"
-        afile.write_bytes(b"aa")
+        with afile.open("wb") as f:
+            f.write(b"aa")
 
         rmtree(adir, force=True)
         assert not adir.exists()
@@ -343,10 +344,10 @@ def attempt_symlink_to(path, to_path):
     """Try to make a symlink from "path" to "to_path", skipping in case this platform
     does not support it or we don't have sufficient privileges (common on Windows)."""
     try:
-        Path(path).symlink_to(Path(to_path))
+        Path(str(path)).symlink_to(Path(to_path))
     except OSError:
         pytest.skip("could not create symbolic link")
 
 
 def test_tmpdir_equals_tmp_path(tmpdir, tmp_path):
-    assert Path(tmpdir) == tmp_path
+    assert Path(str(tmpdir)) == tmp_path