diff --git a/pendulum/locales/cs/__init__.py b/pendulum/locales/cs/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/pendulum/locales/cs/custom.py b/pendulum/locales/cs/custom.py
new file mode 100644
index 0000000..5f66b69
--- /dev/null
+++ b/pendulum/locales/cs/custom.py
@@ -0,0 +1,23 @@
+"""
+cs custom locale file.
+"""
+
+translations = {
+    "units": {"few_second": "pár vteřin"},
+    # Relative time
+    "ago": "{} zpět",
+    "from_now": "za {}",
+    "after": "{0} po",
+    "before": "{0} zpět",
+    # Ordinals
+    "ordinal": {"one": ".", "two": ".", "few": ".", "other": "."},
+    # Date formats
+    "date_formats": {
+        "LTS": "h:mm:ss",
+        "LT": "h:mm",
+        "L": "DD. M. YYYY",
+        "LL": "D. MMMM, YYYY",
+        "LLL": "D. MMMM, YYYY h:mm",
+        "LLLL": "dddd, D. MMMM, YYYY h:mm",
+    },
+}
diff --git a/pendulum/locales/cs/locale.py b/pendulum/locales/cs/locale.py
new file mode 100644
index 0000000..2c51c78
--- /dev/null
+++ b/pendulum/locales/cs/locale.py
@@ -0,0 +1,266 @@
+from .custom import translations as custom_translations
+
+
+"""
+cs locale file.
+
+It has been generated automatically and must not be modified directly.
+"""
+
+
+locale = {
+    "plural": lambda n: "few"
+    if ((n == n and (n >= 2 and n <= 4)) and (0 == 0 and (0 == 0)))
+    else "many"
+    if (not (0 == 0 and (0 == 0)))
+    else "one"
+    if ((n == n and (n == 1)) and (0 == 0 and (0 == 0)))
+    else "other",
+    "ordinal": lambda n: "other",
+    "translations": {
+        "days": {
+            "abbreviated": {
+                0: "ne",
+                1: "po",
+                2: "út",
+                3: "st",
+                4: "čt",
+                5: "pá",
+                6: "so",
+            },
+            "narrow": {
+                0: "N",
+                1: "P",
+                2: "Ú",
+                3: "S",
+                4: "Č",
+                5: "P",
+                6: "S",
+            },
+            "short": {
+                0: "ne",
+                1: "po",
+                2: "út",
+                3: "st",
+                4: "čt",
+                5: "pá",
+                6: "so",
+            },
+            "wide": {
+                0: "neděle",
+                1: "pondělí",
+                2: "úterý",
+                3: "středa",
+                4: "čtvrtek",
+                5: "pátek",
+                6: "sobota",
+            },
+        },
+        "months": {
+            "abbreviated": {
+                1: "led",
+                2: "úno",
+                3: "bře",
+                4: "dub",
+                5: "kvě",
+                6: "čvn",
+                7: "čvc",
+                8: "srp",
+                9: "zář",
+                10: "říj",
+                11: "lis",
+                12: "pro",
+            },
+            "narrow": {
+                1: "1",
+                2: "2",
+                3: "3",
+                4: "4",
+                5: "5",
+                6: "6",
+                7: "7",
+                8: "8",
+                9: "9",
+                10: "10",
+                11: "11",
+                12: "12",
+            },
+            "wide": {
+                1: "ledna",
+                2: "února",
+                3: "března",
+                4: "dubna",
+                5: "května",
+                6: "června",
+                7: "července",
+                8: "srpna",
+                9: "září",
+                10: "října",
+                11: "listopadu",
+                12: "prosince",
+            },
+        },
+        "units": {
+            "year": {
+                "one": "{0} rok",
+                "few": "{0} roky",
+                "many": "{0} roku",
+                "other": "{0} let",
+            },
+            "month": {
+                "one": "{0} měsíc",
+                "few": "{0} měsíce",
+                "many": "{0} měsíce",
+                "other": "{0} měsíců",
+            },
+            "week": {
+                "one": "{0} týden",
+                "few": "{0} týdny",
+                "many": "{0} týdne",
+                "other": "{0} týdnů",
+            },
+            "day": {
+                "one": "{0} den",
+                "few": "{0} dny",
+                "many": "{0} dne",
+                "other": "{0} dní",
+            },
+            "hour": {
+                "one": "{0} hodina",
+                "few": "{0} hodiny",
+                "many": "{0} hodiny",
+                "other": "{0} hodin",
+            },
+            "minute": {
+                "one": "{0} minuta",
+                "few": "{0} minuty",
+                "many": "{0} minuty",
+                "other": "{0} minut",
+            },
+            "second": {
+                "one": "{0} sekunda",
+                "few": "{0} sekundy",
+                "many": "{0} sekundy",
+                "other": "{0} sekund",
+            },
+            "microsecond": {
+                "one": "{0} mikrosekunda",
+                "few": "{0} mikrosekundy",
+                "many": "{0} mikrosekundy",
+                "other": "{0} mikrosekund",
+            },
+        },
+        "relative": {
+            "year": {
+                "future": {
+                    "other": "za {0} let",
+                    "one": "za {0} rok",
+                    "few": "za {0} roky",
+                    "many": "za {0} roku",
+                },
+                "past": {
+                    "other": "před {0} lety",
+                    "one": "před {0} rokem",
+                    "few": "před {0} lety",
+                    "many": "před {0} roku",
+                },
+            },
+            "month": {
+                "future": {
+                    "other": "za {0} měsíců",
+                    "one": "za {0} měsíc",
+                    "few": "za {0} měsíce",
+                    "many": "za {0} měsíce",
+                },
+                "past": {
+                    "other": "před {0} měsíci",
+                    "one": "před {0} měsícem",
+                    "few": "před {0} měsíci",
+                    "many": "před {0} měsíce",
+                },
+            },
+            "week": {
+                "future": {
+                    "other": "za {0} týdnů",
+                    "one": "za {0} týden",
+                    "few": "za {0} týdny",
+                    "many": "za {0} týdne",
+                },
+                "past": {
+                    "other": "před {0} týdny",
+                    "one": "před {0} týdnem",
+                    "few": "před {0} týdny",
+                    "many": "před {0} týdne",
+                },
+            },
+            "day": {
+                "future": {
+                    "other": "za {0} dní",
+                    "one": "za {0} den",
+                    "few": "za {0} dny",
+                    "many": "za {0} dne",
+                },
+                "past": {
+                    "other": "před {0} dny",
+                    "one": "před {0} dnem",
+                    "few": "před {0} dny",
+                    "many": "před {0} dne",
+                },
+            },
+            "hour": {
+                "future": {
+                    "other": "za {0} hodin",
+                    "one": "za {0} hodinu",
+                    "few": "za {0} hodiny",
+                    "many": "za {0} hodiny",
+                },
+                "past": {
+                    "other": "před {0} hodinami",
+                    "one": "před {0} hodinou",
+                    "few": "před {0} hodinami",
+                    "many": "před {0} hodiny",
+                },
+            },
+            "minute": {
+                "future": {
+                    "other": "za {0} minut",
+                    "one": "za {0} minutu",
+                    "few": "za {0} minuty",
+                    "many": "za {0} minuty",
+                },
+                "past": {
+                    "other": "před {0} minutami",
+                    "one": "před {0} minutou",
+                    "few": "před {0} minutami",
+                    "many": "před {0} minuty",
+                },
+            },
+            "second": {
+                "future": {
+                    "other": "za {0} sekund",
+                    "one": "za {0} sekundu",
+                    "few": "za {0} sekundy",
+                    "many": "za {0} sekundy",
+                },
+                "past": {
+                    "other": "před {0} sekundami",
+                    "one": "před {0} sekundou",
+                    "few": "před {0} sekundami",
+                    "many": "před {0} sekundy",
+                },
+            },
+        },
+        "day_periods": {
+            "midnight": "půlnoc",
+            "am": "dop.",
+            "noon": "poledne",
+            "pm": "odp.",
+            "morning1": "ráno",
+            "morning2": "dopoledne",
+            "afternoon1": "odpoledne",
+            "evening1": "večer",
+            "night1": "v noci",
+        },
+    },
+    "custom": custom_translations,
+}

diff --git a/tests/localization/test_cs.py b/tests/localization/test_cs.py
new file mode 100644
index 0000000..f1c6b94
--- /dev/null
+++ b/tests/localization/test_cs.py
@@ -0,0 +1,108 @@
+import pendulum
+
+
+locale = "cs"
+
+
+def test_diff_for_humans():
+    with pendulum.test(pendulum.datetime(2016, 8, 29)):
+        diff_for_humans()
+
+
+def diff_for_humans():
+    d = pendulum.now().subtract(seconds=1)
+    assert d.diff_for_humans(locale=locale) == "pár vteřin zpět"
+
+    d = pendulum.now().subtract(seconds=2)
+    assert d.diff_for_humans(locale=locale) == "pár vteřin zpět"
+
+    d = pendulum.now().subtract(seconds=20)
+    assert d.diff_for_humans(locale=locale) == "před 20 sekundami"
+
+    d = pendulum.now().subtract(minutes=1)
+    assert d.diff_for_humans(locale=locale) == "před 1 minutou"
+
+    d = pendulum.now().subtract(minutes=2)
+    assert d.diff_for_humans(locale=locale) == "před 2 minutami"
+
+    d = pendulum.now().subtract(minutes=5)
+    assert d.diff_for_humans(locale=locale) == "před 5 minutami"
+
+    d = pendulum.now().subtract(hours=1)
+    assert d.diff_for_humans(locale=locale) == "před 1 hodinou"
+
+    d = pendulum.now().subtract(hours=2)
+    assert d.diff_for_humans(locale=locale) == "před 2 hodinami"
+
+    d = pendulum.now().subtract(hours=5)
+    assert d.diff_for_humans(locale=locale) == "před 5 hodinami"
+
+    d = pendulum.now().subtract(days=1)
+    assert d.diff_for_humans(locale=locale) == "před 1 dnem"
+
+    d = pendulum.now().subtract(days=2)
+    assert d.diff_for_humans(locale=locale) == "před 2 dny"
+
+    d = pendulum.now().subtract(weeks=1)
+    assert d.diff_for_humans(locale=locale) == "před 1 týdnem"
+
+    d = pendulum.now().subtract(weeks=2)
+    assert d.diff_for_humans(locale=locale) == "před 2 týdny"
+
+    d = pendulum.now().subtract(months=1)
+    assert d.diff_for_humans(locale=locale) == "před 1 měsícem"
+
+    d = pendulum.now().subtract(months=2)
+    assert d.diff_for_humans(locale=locale) == "před 2 měsíci"
+
+    d = pendulum.now().subtract(months=5)
+    assert d.diff_for_humans(locale=locale) == "před 5 měsíci"
+
+    d = pendulum.now().subtract(years=1)
+    assert d.diff_for_humans(locale=locale) == "před 1 rokem"
+
+    d = pendulum.now().subtract(years=2)
+    assert d.diff_for_humans(locale=locale) == "před 2 lety"
+
+    d = pendulum.now().subtract(years=5)
+    assert d.diff_for_humans(locale=locale) == "před 5 lety"
+
+    d = pendulum.now().add(seconds=1)
+    assert d.diff_for_humans(locale=locale) == "za pár vteřin"
+
+    d = pendulum.now().add(seconds=1)
+    d2 = pendulum.now()
+    assert d.diff_for_humans(d2, locale=locale) == "pár vteřin po"
+    assert d2.diff_for_humans(d, locale=locale) == "pár vteřin zpět"
+
+    assert d.diff_for_humans(d2, True, locale=locale) == "pár vteřin"
+    assert d2.diff_for_humans(d.add(seconds=1), True, locale=locale) == "pár vteřin"
+
+    d = pendulum.now().add(seconds=20)
+    d2 = pendulum.now()
+    assert d.diff_for_humans(d2, locale=locale) == "20 sekund po"
+    assert d2.diff_for_humans(d, locale=locale) == "20 sekund zpět"
+
+    d = pendulum.now().add(seconds=10)
+    d2 = pendulum.now()
+    assert d.diff_for_humans(d2, True, locale=locale) == "pár vteřin"
+    assert d2.diff_for_humans(d.add(seconds=1), True, locale=locale) == "11 sekund"
+
+
+def test_format():
+    d = pendulum.datetime(2016, 8, 29, 7, 3, 6, 123456)
+    assert d.format("dddd", locale=locale) == "pondělí"
+    assert d.format("ddd", locale=locale) == "po"
+    assert d.format("MMMM", locale=locale) == "srpna"
+    assert d.format("MMM", locale=locale) == "srp"
+    assert d.format("A", locale=locale) == "dop."
+    assert d.format("Qo", locale=locale) == "3."
+    assert d.format("Mo", locale=locale) == "8."
+    assert d.format("Do", locale=locale) == "29."
+
+    assert d.format("LT", locale=locale) == "7:03"
+    assert d.format("LTS", locale=locale) == "7:03:06"
+    assert d.format("L", locale=locale) == "29. 8. 2016"
+    assert d.format("LL", locale=locale) == "29. srpna, 2016"
+    assert d.format("LLL", locale=locale) == "29. srpna, 2016 7:03"
+    assert d.format("LLLL", locale=locale) == "pondělí, 29. srpna, 2016 7:03"

Missing Czech [cs] locale
- [x] I have searched the [issues](https://github.com/sdispater/pendulum/issues) of this repo and believe that this is not a duplicate.
- [x] I have searched the [documentation](https://pendulum.eustace.io/docs/) and believe that my question is not covered.

## Feature Request

Missing localization for Czech language.

I will take care of the code and open PR.
tests/localization/test_cs.py::test_diff_for_humans tests/localization/test_cs.py::test_format