diff --git a/CONTRIBUTORS.txt b/CONTRIBUTORS.txt
index f1d54dbd5c2..c0865d0c6d6 100644
--- a/CONTRIBUTORS.txt
+++ b/CONTRIBUTORS.txt
@@ -521,3 +521,5 @@ contributors:
 * Yilei Yang: contributor
 
 * Marcin Kurczewski (rr-): contributor
+
+* Daniel van Noord (DanielNoord): contributor
diff --git a/ChangeLog b/ChangeLog
index 778e863939b..52ce722f3df 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,10 @@ Release date: TBA
 ..
   Put new features here and also in 'doc/whatsnew/2.10.rst'
 
+* Added ``unspecified-encoding``: Emitted when open() is called without specifying an encoding
+
+  Closes #3826
+
 
 What's New in Pylint 2.9.6?
 ===========================
diff --git a/doc/whatsnew/2.10.rst b/doc/whatsnew/2.10.rst
index 3e17dc78174..ee717524ada 100644
--- a/doc/whatsnew/2.10.rst
+++ b/doc/whatsnew/2.10.rst
@@ -12,7 +12,9 @@ Summary -- Release highlights
 New checkers
 ============
 
+* Added ``unspecified-encoding``: Emitted when open() is called without specifying an encoding
 
+  Closes #3826
 
 Other Changes
 =============
diff --git a/pylint/checkers/stdlib.py b/pylint/checkers/stdlib.py
index c0e789ad874..732a51fa7fe 100644
--- a/pylint/checkers/stdlib.py
+++ b/pylint/checkers/stdlib.py
@@ -30,6 +30,7 @@
 # Copyright (c) 2021 Marc Mueller <30130371+cdce8p@users.noreply.github.com>
 # Copyright (c) 2021 Matus Valo <matusvalo@users.noreply.github.com>
 # Copyright (c) 2021 victor <16359131+jiajunsu@users.noreply.github.com>
+# Copyright (c) 2021 Daniel van Noord <13665637+DanielNoord@users.noreply.github.com>
 
 # Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 # For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
@@ -425,6 +426,13 @@ class StdlibChecker(DeprecatedMixin, BaseChecker):
             "deprecated-decorator",
             "The decorator is marked as deprecated and will be removed in the future.",
         ),
+        "W1514": (
+            "Using open without explicitly specifying an encoding",
+            "unspecified-encoding",
+            "It is better to specify an encoding when opening documents. "
+            "Using the system default implicitly can create problems on other operating systems. "
+            "See https://www.python.org/dev/peps/pep-0597/",
+        ),
     }
 
     def __init__(self, linter=None):
@@ -485,6 +493,7 @@ def _check_shallow_copy_environ(self, node):
         "subprocess-popen-preexec-fn",
         "subprocess-run-check",
         "deprecated-class",
+        "unspecified-encoding",
     )
     def visit_call(self, node):
         """Visit a Call node."""
@@ -496,6 +505,8 @@ def visit_call(self, node):
                 if inferred.root().name == OPEN_MODULE:
                     if getattr(node.func, "name", None) in OPEN_FILES:
                         self._check_open_mode(node)
+                    if getattr(node.func, "name", None) == "open":
+                        self._check_open_encoded(node)
                 elif inferred.root().name == UNITTEST_CASE:
                     self._check_redundant_assert(node, inferred)
                 elif isinstance(inferred, astroid.ClassDef):
@@ -573,6 +584,34 @@ def _check_open_mode(self, node):
             ):
                 self.add_message("bad-open-mode", node=node, args=mode_arg.value)
 
+    def _check_open_encoded(self, node: astroid.Call) -> None:
+        """Check that the encoded argument of an open call is valid."""
+        mode_arg = None
+        try:
+            mode_arg = utils.get_argument_from_call(node, position=1, keyword="mode")
+        except utils.NoSuchArgumentError:
+            pass
+
+        if mode_arg:
+            mode_arg = utils.safe_infer(mode_arg)
+        if not mode_arg or "b" not in mode_arg.value:
+            encoding_arg = None
+            try:
+                encoding_arg = utils.get_argument_from_call(
+                    node, position=None, keyword="encoding"
+                )
+            except utils.NoSuchArgumentError:
+                self.add_message("unspecified-encoding", node=node)
+
+            if encoding_arg:
+                encoding_arg = utils.safe_infer(encoding_arg)
+
+                if (
+                    isinstance(encoding_arg, astroid.Const)
+                    and encoding_arg.value is None
+                ):
+                    self.add_message("unspecified-encoding", node=node)
+
     def _check_env_function(self, node, infer):
         env_name_kwarg = "key"
         env_value_kwarg = "default"
diff --git a/tests/functional/u/unspecified_encoding_py3.py b/tests/functional/u/unspecified_encoding_py3.py
new file mode 100644
index 00000000000..11ce156269c
--- /dev/null
+++ b/tests/functional/u/unspecified_encoding_py3.py
@@ -0,0 +1,30 @@
+"""Warnings for using open() without specifying an encoding"""
+# pylint: disable=consider-using-with
+import locale
+
+FILENAME = "foo.bar"
+open(FILENAME, "w", encoding="utf-8")
+open(FILENAME, "wb")
+open(FILENAME, "w+b")
+open(FILENAME)  # [unspecified-encoding]
+open(FILENAME, "wt")  # [unspecified-encoding]
+open(FILENAME, "w+")  # [unspecified-encoding]
+open(FILENAME, "w", encoding=None)  # [unspecified-encoding]
+open(FILENAME, "r")  # [unspecified-encoding]
+
+with open(FILENAME, encoding="utf8", errors="surrogateescape") as f:
+    pass
+
+LOCALE_ENCODING = locale.getlocale()[1]
+with open(FILENAME, encoding=LOCALE_ENCODING) as f:
+    pass
+
+with open(FILENAME) as f:  # [unspecified-encoding]
+    pass
+
+with open(FILENAME, encoding=None) as f:  # [unspecified-encoding]
+    pass
+
+LOCALE_ENCODING = None
+with open(FILENAME, encoding=LOCALE_ENCODING) as f:  # [unspecified-encoding]
+    pass
diff --git a/tests/functional/u/unspecified_encoding_py3.txt b/tests/functional/u/unspecified_encoding_py3.txt
new file mode 100644
index 00000000000..5f0cf89d774
--- /dev/null
+++ b/tests/functional/u/unspecified_encoding_py3.txt
@@ -0,0 +1,8 @@
+unspecified-encoding:9:0::"Using open without explicitly specifying an encoding"
+unspecified-encoding:10:0::"Using open without explicitly specifying an encoding"
+unspecified-encoding:11:0::"Using open without explicitly specifying an encoding"
+unspecified-encoding:12:0::"Using open without explicitly specifying an encoding"
+unspecified-encoding:13:0::"Using open without explicitly specifying an encoding"
+unspecified-encoding:22:5::"Using open without explicitly specifying an encoding"
+unspecified-encoding:25:5::"Using open without explicitly specifying an encoding"
+unspecified-encoding:29:5::"Using open without explicitly specifying an encoding"