ImportError: cannot import name from partially initialized module (most likely due to a circular import)

What you see

from customers import Customer

class Order:
    def __init__(self, customer: Customer):
        self.customer = customer

from orders import Order

class Customer:
    def new_order(self) -> Order:
        return Order(self)

import orders

Traceback (most recent call last):
  File "/home/me/project/main.py", line 1, in <module>
    import orders
  File "/home/me/project/orders.py", line 1, in <module>
    from customers import Customer
  File "/home/me/project/customers.py", line 1, in <module>
    from orders import Order
ImportError: cannot import name 'Order' from 'orders' (consider renaming '/home/me/project/orders.py' if it has the same name as a library you intended to import)

What it means

Python runs a module from top to bottom the first time it is imported. Here orders starts running, and its first line imports customers. customers, in turn, asks for Order from orders, but orders has only got as far as its first line: class Order has not run yet. That half-run module is what "partially initialized" means.

Python 3.13 and later word the same failure differently, and less helpfully: they drop "partially initialized" and suggest renaming orders.py in case it shadows a library. Unless your file really has a library's name, the cause is still the loop.

The cycle is the problem, not either file on its own. Each import is fine; together they wait for each other.

Why it happens

• Two modules that need each other's names at import time, as in the example: models that refer to each other, or a helper module that imports the module that uses it.
• Imports added only for type hints that create a loop the code itself does not need.
• A file of yours named like a module it imports, such as random.py doing import random. That is a loop of one file with itself; it has its own page.

How to fix it

Move what both need into a third module. If orders and customers both need a base class or constants, put them in models.py and import from there. This is the fix that removes the loop.

Import the module, not the name, and look the name up when the code runs:

import orders

class Customer:
    def new_order(self):
        return orders.Order(self)

Import inside the function that needs it, so the import runs at call time, after both modules have loaded:

class Customer:
    def new_order(self):
        from orders import Order
        return Order(self)

For imports used only in type hints, guard them with TYPE_CHECKING, which is false when the program runs:

from __future__ import annotations
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from orders import Order

How each Python version words it

Run on CPython 3.9.6, 3.10.22, 3.11.17, 3.12.15, 3.13.17, 3.14.9 and 3.15.1, on October 25, 2026.

3.9 to 3.12 name the cause: "from partially initialized module 'orders' (most likely due to a circular import)". 3.13 and later print "cannot import name 'Order' from 'orders'" with a hint to rename the file, the hint added for files that shadow a library.

Python 3.14 evaluates annotations lazily, but the from orders import Order line still runs at import time, so the loop fails there just the same.