Are Python Dictionaries Ordered? Yes, Since 3.7
Insertion order is a language guarantee, not an implementation accident.
Aditya Challa1 min read
Summary
Yes, Python dictionaries preserve insertion order, and the language has guaranteed it since Python 3.7. Iterating over a dict, or its keys, values and items, returns entries in the order they were first inserted.
What "ordered" means here
Updating an existing key keeps its original position. Deleting a key and adding it again moves it to the end.
Version history
The Python docs note: "Changed in version 3.7: Dictionary order is guaranteed to be insertion order." CPython 3.6 already behaved this way as an implementation detail.
When to use OrderedDict
collections.OrderedDict still adds move_to_end() and treats order as significant when comparing two OrderedDicts for equality, which plain dicts do not.
Related: /blog/is-python-3-14-free-threaded-by-default
Related: /blog/what-does-if-name-main-do-in-python
Sources
Lab evidence
What I found running this
Facts in this draft were checked on 12 Oct 2026 against the primary sources listed in the body (official docs, release schedules or Google/YouTube help pages). No benchmarks or timings were run, so the post makes no performance or measurement claims; dates are quoted as published by the maintainers, and any estimate is labelled as such.
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