diff --git a/docs/categories.md b/docs/categories.md
new file mode 100644
index 0000000..c97feac
--- /dev/null
+++ b/docs/categories.md
@@ -0,0 +1,100 @@
+# Categories
+
+Here is a list of the built-in categories in Refurb, and their meanings.
+
+## `builtin`
+
+Checks that have the `builtin` category cover a few different topics:
+
+* Built-in functions such as `print()`, `open()`, `str()`, and so on
+* Statements such as `del`
+* File system related operations such as `open()` and `readlines()`
+
+## `control-flow`
+
+These checks deal with the control flow of a program, such as optimizing usage
+of `return` and `continue`, removing `if` statements under certain conditions,
+and so on.
+
+## `contextlib`
+
+These checks are for the [contextlib](https://docs.python.org/3/library/contextlib.html)
+standard library module.
+
+## `dict`
+
+These checks cover:
+
+* Usage of `dict` objects
+* In some cases, objects supporting the [Mapping](https://docs.python.org/3/library/collections.abc.html#collections.abc.Mapping) protocol
+
+## `fstring`
+
+These checks relate to Python's [f-strings](https://fstring.help/).
+
+## `functools`
+
+These checks relate to the [functools](https://docs.python.org/3/library/functools.html)
+standard library module.
+
+## `iterable`
+
+These checks cover:
+
+* Iterable types such as `list` and `tuple`
+* Standard library objects which are commonly iterated over such as `dict` keys
+
+## `itertools`
+
+These checks relate to the [itertools](https://docs.python.org/3/library/itertools.html)
+standard library module.
+
+## `operator`
+
+These checks relate to the [operator](https://docs.python.org/3/library/operator.html)
+standard library module.
+
+## `logical`
+
+These checks relate to logical cleanups and optimizations, primarily in `if` statements,
+but also in boolean expressions.
+
+## `list`
+
+These checks cover usage of the built-in `list` object.
+
+## `pathlib`
+
+These checks relate to the [pathlib](https://docs.python.org/3/library/pathlib.html)
+standard library module.
+
+## `pythonic`
+
+This is a general catch-all for things which are "unpythonic". It differs from the
+`readability` category because "unreadable" code can still be pythonic.
+
+## `readability`
+
+These checks aim to make existing code more readable. This can be subjective, but in general,
+they reduce the horizontal or vertical length of your code, or make the underlying meaning
+of the code more apparent.
+
+## `scoping`
+
+These checks have to do with Python's scoping rules. For more info on how Python's scoping
+rules work, read [this article](https://realpython.com/python-scope-legb-rule/).
+
+## `string`
+
+These checks deal with usage of [`str`](https://docs.python.org/3/library/stdtypes.html#string-methods)
+objects in Python.
+
+## `set`
+
+These checks deal with usage of [`set`](https://docs.python.org/3/tutorial/datastructures.html#sets)
+objects in Python.
+
+## `truthy`
+
+These checks cover truthy and falsy operations in Python, primarily in the context of `assert` and `if`
+statements.
diff --git a/refurb/checks/builtin/list_extend.py b/refurb/checks/builtin/list_extend.py
index ad091ad..9e0fd69 100644
--- a/refurb/checks/builtin/list_extend.py
+++ b/refurb/checks/builtin/list_extend.py
@@ -42,6 +42,7 @@ class ErrorInfo(Error):
 
     code = 113
     msg: str = "Use `x.extend(...)` instead of repeatedly calling `x.append()`"
+    categories = ["list"]
 
 
 @dataclass
diff --git a/refurb/checks/builtin/no_del.py b/refurb/checks/builtin/no_del.py
index 87f916c..18a7913 100644
--- a/refurb/checks/builtin/no_del.py
+++ b/refurb/checks/builtin/no_del.py
@@ -39,6 +39,7 @@ class ErrorInfo(Error):
     """
 
     code = 131
+    categories = ["builtin", "readability"]
 
 
 def check(node: DelStmt, errors: list[Error]) -> None:
diff --git a/refurb/checks/builtin/no_ignored_dict_items.py b/refurb/checks/builtin/no_ignored_dict_items.py
index 7f43011..9e80394 100644
--- a/refurb/checks/builtin/no_ignored_dict_items.py
+++ b/refurb/checks/builtin/no_ignored_dict_items.py
@@ -48,6 +48,7 @@ class ErrorInfo(Error):
     """
 
     code = 135
+    categories = ["dict"]
 
 
 def check(
diff --git a/refurb/checks/builtin/print.py b/refurb/checks/builtin/print.py
index d506a28..d8a437a 100644
--- a/refurb/checks/builtin/print.py
+++ b/refurb/checks/builtin/print.py
@@ -13,6 +13,7 @@ class ErrorInfo(Error):
 
     code = 105
     msg: str = 'Replace `print("")` with `print()`'
+    categories = ["builtin", "readability"]
 
 
 def check(node: CallExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/builtin/set_discard.py b/refurb/checks/builtin/set_discard.py
index e42e018..967619f 100644
--- a/refurb/checks/builtin/set_discard.py
+++ b/refurb/checks/builtin/set_discard.py
@@ -41,6 +41,7 @@ class ErrorInfo(Error):
 
     code = 132
     msg: str = "Replace `if x in s: s.remove(x)` with `s.discard(x)`"
+    categories = ["readability", "set"]
 
 
 def check(node: IfStmt, errors: list[Error]) -> None:
diff --git a/refurb/checks/builtin/use_isinstance_tuple.py b/refurb/checks/builtin/use_isinstance_tuple.py
index 8a8a8ba..2981076 100644
--- a/refurb/checks/builtin/use_isinstance_tuple.py
+++ b/refurb/checks/builtin/use_isinstance_tuple.py
@@ -38,6 +38,7 @@ class ErrorInfo(Error):
     """
 
     code = 121
+    categories = ["readability"]
 
 
 def check(node: OpExpr, errors: list[Error], settings: Settings) -> None:
diff --git a/refurb/checks/builtin/writelines.py b/refurb/checks/builtin/writelines.py
index 07c2807..7223771 100644
--- a/refurb/checks/builtin/writelines.py
+++ b/refurb/checks/builtin/writelines.py
@@ -49,6 +49,7 @@ class ErrorInfo(Error):
 
     code = 122
     msg: str = "Replace `for line in lines: f.write(line)` with `f.writelines(lines)`"  # noqa: E501
+    categories = ["builtin", "readability"]
 
 
 def check(node: WithStmt, errors: list[Error]) -> None:
diff --git a/refurb/checks/contextlib/with_suppress.py b/refurb/checks/contextlib/with_suppress.py
index c0604d3..8ff8500 100644
--- a/refurb/checks/contextlib/with_suppress.py
+++ b/refurb/checks/contextlib/with_suppress.py
@@ -32,6 +32,7 @@ class ErrorInfo(Error):
     """
 
     code = 107
+    categories = ["contextlib", "readability"]
 
 
 def check(node: TryStmt, errors: list[Error]) -> None:
diff --git a/refurb/checks/flow/no_trailing_continue.py b/refurb/checks/flow/no_trailing_continue.py
index 999dc7d..4c63b8d 100644
--- a/refurb/checks/flow/no_trailing_continue.py
+++ b/refurb/checks/flow/no_trailing_continue.py
@@ -61,6 +61,7 @@ def func2(x):
 
     code = 133
     msg: str = "Continue is redundant here"
+    categories = ["control-flow", "readability"]
 
 
 def get_trailing_continue(node: Statement) -> Generator[Statement, None, None]:
diff --git a/refurb/checks/flow/no_trailing_return.py b/refurb/checks/flow/no_trailing_return.py
index 91469d4..3afb4b8 100644
--- a/refurb/checks/flow/no_trailing_return.py
+++ b/refurb/checks/flow/no_trailing_return.py
@@ -56,6 +56,7 @@ def func2(x):
 
     code = 125
     msg: str = "Return is redundant here"
+    categories = ["control-flow", "readability"]
 
 
 def get_trailing_return(node: Statement) -> Generator[Statement, None, None]:
diff --git a/refurb/checks/flow/no_with_assign.py b/refurb/checks/flow/no_with_assign.py
index 47568f9..eca9be8 100644
--- a/refurb/checks/flow/no_with_assign.py
+++ b/refurb/checks/flow/no_with_assign.py
@@ -41,6 +41,7 @@ class ErrorInfo(Error):
 
     code = 127
     msg: str = "This variable is redeclared later, and can be removed here"
+    categories = ["readability", "scoping"]
 
 
 def check(node: Block | MypyFile, errors: list[Error]) -> None:
diff --git a/refurb/checks/flow/simplify_return.py b/refurb/checks/flow/simplify_return.py
index 1c14e2d..c137a9c 100644
--- a/refurb/checks/flow/simplify_return.py
+++ b/refurb/checks/flow/simplify_return.py
@@ -57,6 +57,7 @@ def is_on_axis(position: tuple[int, int]) -> bool:
     """
 
     code = 126
+    categories = ["control-flow", "readability"]
 
 
 def get_trailing_return(node: Statement) -> Statement | None:
diff --git a/refurb/checks/functools/use_cache.py b/refurb/checks/functools/use_cache.py
index 7e9a0ac..0d403fd 100644
--- a/refurb/checks/functools/use_cache.py
+++ b/refurb/checks/functools/use_cache.py
@@ -35,6 +35,7 @@ def f(x: int) -> int:
 
     code = 134
     msg: str = "Replace `@lru_cache(maxsize=None)` with `@cache`"
+    categories = ["functools", "readability"]
 
 
 def check(node: Decorator, errors: list[Error], settings: Settings) -> None:
diff --git a/refurb/checks/iterable/implicit_readlines.py b/refurb/checks/iterable/implicit_readlines.py
index 0c24c93..c262a37 100644
--- a/refurb/checks/iterable/implicit_readlines.py
+++ b/refurb/checks/iterable/implicit_readlines.py
@@ -39,6 +39,7 @@ class ErrorInfo(Error):
 
     code = 129
     msg: str = "Replace `f.readlines()` with `f`"
+    categories = ["builtin", "readability"]
 
 
 def get_readline_file_object(expr: Expression) -> NameExpr | None:
diff --git a/refurb/checks/iterable/in_tuple.py b/refurb/checks/iterable/in_tuple.py
index 314099d..da16ecc 100644
--- a/refurb/checks/iterable/in_tuple.py
+++ b/refurb/checks/iterable/in_tuple.py
@@ -31,6 +31,7 @@ class ErrorInfo(Error):
     """
 
     code = 109
+    categories = ["iterable", "readability"]
 
 
 def error_msg(oper: str) -> str:
diff --git a/refurb/checks/logical/use_equal_chain.py b/refurb/checks/logical/use_equal_chain.py
index 65bbb5c..8049d5c 100644
--- a/refurb/checks/logical/use_equal_chain.py
+++ b/refurb/checks/logical/use_equal_chain.py
@@ -32,6 +32,7 @@ class ErrorInfo(Error):
 
     code = 124
     msg: str = "Replace `x == y and x == z` with `x == y == z`"
+    categories = ["logical", "readability"]
 
 
 def has_common_expr(*exprs: Expression) -> bool:
diff --git a/refurb/checks/logical/use_in.py b/refurb/checks/logical/use_in.py
index 670cdba..95a6e57 100644
--- a/refurb/checks/logical/use_in.py
+++ b/refurb/checks/logical/use_in.py
@@ -33,6 +33,7 @@ class ErrorInfo(Error):
 
     code = 108
     msg: str = "Replace `x == y or x == z` with `x in (y, z)`"
+    categories = ["logical", "readability"]
 
 
 def check(node: OpExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/logical/use_or.py b/refurb/checks/logical/use_or.py
index 9bb648c..bee2960 100644
--- a/refurb/checks/logical/use_or.py
+++ b/refurb/checks/logical/use_or.py
@@ -29,6 +29,7 @@ class ErrorInfo(Error):
 
     code = 110
     msg: str = "Replace `x if x else y` with `x or y`"
+    categories = ["logical", "readability"]
 
 
 def check(node: ConditionalExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/pathlib/cwd.py b/refurb/checks/pathlib/cwd.py
index 65827d9..f94aeda 100644
--- a/refurb/checks/pathlib/cwd.py
+++ b/refurb/checks/pathlib/cwd.py
@@ -25,6 +25,7 @@ class ErrorInfo(Error):
 
     code = 104
     msg: str = "Replace `os.getcwd()` with `Path.cwd()`"
+    categories = ["pathlib"]
 
 
 def check(node: CallExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/pathlib/open.py b/refurb/checks/pathlib/open.py
index e583d4f..c1befba 100644
--- a/refurb/checks/pathlib/open.py
+++ b/refurb/checks/pathlib/open.py
@@ -32,6 +32,7 @@ class ErrorInfo(Error):
     """
 
     code = 117
+    categories = ["pathlib"]
 
 
 def check(node: CallExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/pathlib/read_text.py b/refurb/checks/pathlib/read_text.py
index 766f7b5..9f97d26 100644
--- a/refurb/checks/pathlib/read_text.py
+++ b/refurb/checks/pathlib/read_text.py
@@ -35,6 +35,7 @@ class ErrorInfo(Error):
     """
 
     code = 101
+    categories = ["pathlib"]
 
 
 def check(node: WithStmt, errors: list[Error]) -> None:
diff --git a/refurb/checks/pathlib/with_suffix.py b/refurb/checks/pathlib/with_suffix.py
index 66481f6..9f3495f 100644
--- a/refurb/checks/pathlib/with_suffix.py
+++ b/refurb/checks/pathlib/with_suffix.py
@@ -36,6 +36,7 @@ class ErrorInfo(Error):
 
     code = 100
     msg: str = "Use `Path(x).with_suffix(y)` instead of slice and concat"  # noqa: E501
+    categories = ["pathlib"]
 
 
 def check(node: OpExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/pathlib/write_text.py b/refurb/checks/pathlib/write_text.py
index 45e6e49..636f77f 100644
--- a/refurb/checks/pathlib/write_text.py
+++ b/refurb/checks/pathlib/write_text.py
@@ -34,6 +34,7 @@ class ErrorInfo(Error):
     """
 
     code = 103
+    categories = ["pathlib"]
 
 
 def check(node: WithStmt, errors: list[Error]) -> None:
diff --git a/refurb/checks/readability/in_keys.py b/refurb/checks/readability/in_keys.py
index 3e7b3a8..8fe739d 100644
--- a/refurb/checks/readability/in_keys.py
+++ b/refurb/checks/readability/in_keys.py
@@ -31,6 +31,7 @@ class ErrorInfo(Error):
     """
 
     code = 130
+    categories = ["dict", "readability"]
 
 
 def check(node: ComparisonExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/readability/no_double_not.py b/refurb/checks/readability/no_double_not.py
index b99ef0f..d4d5a7b 100644
--- a/refurb/checks/readability/no_double_not.py
+++ b/refurb/checks/readability/no_double_not.py
@@ -27,6 +27,7 @@ class ErrorInfo(Error):
 
     code = 114
     msg: str = "Replace `not not x` with `bool(x)`"
+    categories = ["builtin", "readability", "truthy"]
 
 
 def check(node: UnaryExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/readability/no_len_cmp.py b/refurb/checks/readability/no_len_cmp.py
index 4fe5d2c..fdf6bd2 100644
--- a/refurb/checks/readability/no_len_cmp.py
+++ b/refurb/checks/readability/no_len_cmp.py
@@ -60,6 +60,7 @@ class ErrorInfo(Error):
     """
 
     code = 115
+    categories = ["iterable", "truthy"]
 
 
 CONTAINER_TYPES = {
diff --git a/refurb/checks/readability/no_unnecessary_cast.py b/refurb/checks/readability/no_unnecessary_cast.py
index 7e659e4..ad763eb 100644
--- a/refurb/checks/readability/no_unnecessary_cast.py
+++ b/refurb/checks/readability/no_unnecessary_cast.py
@@ -53,6 +53,7 @@ class ErrorInfo(Error):
     """
 
     code = 123
+    categories = ["readability"]
 
 
 FUNC_NAMES = {
diff --git a/refurb/checks/readability/use_func_name.py b/refurb/checks/readability/use_func_name.py
index d381a60..7f5b905 100644
--- a/refurb/checks/readability/use_func_name.py
+++ b/refurb/checks/readability/use_func_name.py
@@ -39,6 +39,7 @@ class ErrorInfo(Error):
 
     code = 111
     msg: str = "Replace `lambda x: f(x)` with `f`"
+    categories = ["readability"]
 
 
 def get_lambda_arg_names(args: list[Argument]) -> list[str]:
diff --git a/refurb/checks/readability/use_literal.py b/refurb/checks/readability/use_literal.py
index 318c7b6..25286e2 100644
--- a/refurb/checks/readability/use_literal.py
+++ b/refurb/checks/readability/use_literal.py
@@ -27,6 +27,7 @@ class ErrorInfo(Error):
     """
 
     code = 112
+    categories = ["pythonic", "readability"]
 
 
 FUNC_NAMES = {
diff --git a/refurb/checks/readability/use_operators.py b/refurb/checks/readability/use_operators.py
index 368cef6..8c2258c 100644
--- a/refurb/checks/readability/use_operators.py
+++ b/refurb/checks/readability/use_operators.py
@@ -44,6 +44,7 @@ class ErrorInfo(Error):
     """
 
     code = 118
+    categories = ["operator"]
 
 
 BINARY_OPERATORS = {
diff --git a/refurb/checks/readability/use_tuple_swap.py b/refurb/checks/readability/use_tuple_swap.py
index 9843137..0a46625 100644
--- a/refurb/checks/readability/use_tuple_swap.py
+++ b/refurb/checks/readability/use_tuple_swap.py
@@ -29,6 +29,7 @@ class ErrorInfo(Error):
 
     code = 128
     msg: str = "Use tuple unpacking instead of temporary variables to swap values"  # noqa: E501
+    categories = ["readability"]
 
 
 def check(node: Block | MypyFile, errors: list[Error]) -> None:
diff --git a/refurb/checks/string/expandtabs.py b/refurb/checks/string/expandtabs.py
index f17c94b..5486779 100644
--- a/refurb/checks/string/expandtabs.py
+++ b/refurb/checks/string/expandtabs.py
@@ -38,6 +38,7 @@ class ErrorInfo(Error):
 
     enabled = False
     code = 106
+    categories = ["string"]
 
 
 def check_str(node: CallExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/string/fstring_number.py b/refurb/checks/string/fstring_number.py
index c8a4e9b..84e322d 100644
--- a/refurb/checks/string/fstring_number.py
+++ b/refurb/checks/string/fstring_number.py
@@ -27,6 +27,7 @@ class ErrorInfo(Error):
     """
 
     code = 116
+    categories = ["builtin", "fstring"]
 
 
 FUNC_CONVERSIONS = {
diff --git a/refurb/checks/string/startswith.py b/refurb/checks/string/startswith.py
index c5a2ae7..4a2ea54 100644
--- a/refurb/checks/string/startswith.py
+++ b/refurb/checks/string/startswith.py
@@ -31,6 +31,7 @@ class ErrorInfo(Error):
     """
 
     code = 102
+    categories = ["string"]
 
 
 def check(node: OpExpr, errors: list[Error]) -> None:
diff --git a/refurb/checks/string/use_fstring_fmt.py b/refurb/checks/string/use_fstring_fmt.py
index d48fced..624ec5f 100644
--- a/refurb/checks/string/use_fstring_fmt.py
+++ b/refurb/checks/string/use_fstring_fmt.py
@@ -33,6 +33,7 @@ class ErrorInfo(Error):
     """
 
     code = 119
+    categories = ["builtin", "fstring"]
 
 
 CONVERSIONS = {
diff --git a/refurb/error.py b/refurb/error.py
index d75e97a..b1a26ec 100644
--- a/refurb/error.py
+++ b/refurb/error.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import ClassVar, Optional
+from typing import ClassVar
 
 
 @dataclass(frozen=True)
@@ -25,7 +25,8 @@ class Error:
     line: int
     column: int
     msg: str
-    filename: Optional[str] = None
+    filename: str | None = None
+    categories: list[str] | None = None
 
     def __str__(self) -> str:
         return f"{self.filename}:{self.line}:{self.column + 1} [{self.prefix}{self.code}]: {self.msg}"  # noqa: E501
diff --git a/test/test_category_naming.py b/test/test_category_naming.py
new file mode 100644
index 0000000..5a71baf
--- /dev/null
+++ b/test/test_category_naming.py
@@ -0,0 +1,37 @@
+import re
+from pathlib import Path
+
+import refurb
+from refurb.loader import get_error_class, get_modules
+
+
+def test_check_categories_are_valid() -> None:
+    # By "valid" I mean that they are well-defined (in the documentation), and
+    # are sorted. Basically, parse the documentation file for the categories,
+    # which includes a list of all categories, and make sure each check only
+    # uses categories defined in that list. This prevents typos from causing
+    # a check to have an incorrect category.
+
+    category_docs = Path(refurb.__file__).parent.parent / "docs/categories.md"
+
+    with category_docs.open() as f:
+        categories = []
+
+        for line in f:
+            if name := re.search("## `([a-z-]+)`", line):
+                categories.append(name.group(1))
+
+    for module in get_modules([]):
+        error = get_error_class(module)
+
+        if not error or not error.categories:
+            continue
+
+        error_msg = f'{module.__file__}: categories for "{error.__name__}" class are not sorted'
+
+        assert sorted(error.categories) == error.categories, error_msg
+
+        for category in error.categories:
+            assert (
+                category in categories
+            ), f'{module.__file__}: category "{category}" is invalid'