SyntaxError: invalid syntax — how to fix

  File "script.py", line 4
    if x = 5:
       ^
SyntaxError: invalid syntax

Quick fix: Look at the caret and the line above it. Check for unclosed ( [ { or quotes on earlier lines, a missing : after if/for/def, = instead of ==, Python 2 code like print "x", or new syntax (match, walrus :=) on an older Python — check python --version.

What it means

The parser hit a token it didn't expect. Nothing in the file runs — syntax errors are reported before execution. Recent Python versions (3.10+) give much more specific messages like '(' was never closed or expected ':'; on older versions you just get invalid syntax. If you can, run the file with a newer Python to get a better hint.

Cause 1: unclosed bracket or quote on a previous line

data = {"a": 1, "b": [1, 2, 3}
print(data)        # error is reported here (or above)

The parser only notices when the next line doesn't make sense. Count brackets on the lines before the caret. An editor with bracket matching makes this quick.

Cause 2: missing colon

def greet(name)      # missing :
    print(name)

for i in range(3)    # missing :

Every if, elif, else, for, while, def, class, try, except, finally, with and match/case line ends with :.

Cause 3: = instead of ==

if x = 5:      # assignment isn't allowed here
if x == 5:     # comparison

Python 3.10+ says Maybe you meant '==' or ':=' instead of '='?.

Cause 4: Python 2 code

print "hello"                 # Python 2
print("hello")                # Python 3

except Exception, e:          # Python 2
except Exception as e:        # Python 3

Old tutorials and scripts often have this. Running python may also start Python 2 on old systems — check with python --version and use python3.

Cause 5: syntax newer than your interpreter

• match/case needs Python 3.10+
• := (walrus) needs 3.8+
• f-strings need 3.6+; nested same-type quotes inside f-strings (f"{d["k"]}") need 3.12+
• X | Y type unions in annotations evaluate at runtime only on 3.10+ (that one is a TypeError, not a syntax error)

python3 --version

Upgrade Python or rewrite the line (e.g. f"{d['k']}").

Cause 6: running shell commands inside Python

>>> pip install requests
  File "<stdin>", line 1
    pip install requests
        ^^^^^^^
SyntaxError: invalid syntax

pip, python script.py, cd etc. are terminal commands. Exit the REPL with exit() and run them in your shell. In Jupyter, use %pip install requests.

Cause 7: reserved words as names

class = "A"     # invalid
from = 1        # invalid
lambda = 0.5    # invalid

Rename (cls, from_, lam). See the list with import keyword; print(keyword.kwlist).

Cause 8: invisible or smart characters

Code copied from web pages or docs may contain curly quotes (“ ”) or non-breaking spaces. Python 3 reports invalid character '“' (U+201C). Retype the quotes, or find them:

grep -nP '[^\x00-\x7F]' script.py

Getting the exact location

python3 -m py_compile script.py

reports the first syntax error with line and column without running anything.

Last updated 2026-11-03.