Turn off autocorrect on Mac completely

If you're done with macOS second-guessing your typing, note that "autocorrect" is really a bundle of separate behaviors — spelling correction, auto-capitalization, the double-space period, and smart quotes and dashes. Turning off one leaves the others running. Here's every switch in one place, in System Settings and in Terminal, so you can shut the whole thing down for good.

The one screen with all the switches

1. Open System Settings → Keyboard.
2. In the Text Input section, click Edit….
3. Turn off Correct spelling automatically.
4. Turn off Capitalize words automatically.
5. Turn off Add full stop with double-space (shown as "Add period with double-space" in some regions).
6. Turn off Use smart quotes and dashes.
7. Click Done.

That sheet is the same on macOS 13 Ventura, 14 Sonoma, and 15 Sequoia. With all four off, macOS stops transforming your text entirely.

Turn them all off in Terminal

Setting up a fresh Mac or scripting your dotfiles? Each behavior is a key in NSGlobalDomain:

# disable every smart-typing behavior
defaults write NSGlobalDomain NSAutomaticSpellingCorrectionEnabled -bool false
defaults write NSGlobalDomain NSAutomaticCapitalizationEnabled -bool false
defaults write NSGlobalDomain NSAutomaticPeriodSubstitutionEnabled -bool false
defaults write NSGlobalDomain NSAutomaticQuoteSubstitutionEnabled -bool false
defaults write NSGlobalDomain NSAutomaticDashSubstitutionEnabled -bool false

# undo — hand every setting back to macOS defaults
defaults delete NSGlobalDomain NSAutomaticSpellingCorrectionEnabled
defaults delete NSGlobalDomain NSAutomaticCapitalizationEnabled
defaults delete NSGlobalDomain NSAutomaticPeriodSubstitutionEnabled
defaults delete NSGlobalDomain NSAutomaticQuoteSubstitutionEnabled
defaults delete NSGlobalDomain NSAutomaticDashSubstitutionEnabled

No logout is required, but apps read these when they launch — quit and reopen each app (or log out and back in) so nothing keeps the old behavior. Each key maps one-to-one to a checkbox above, so you can turn off just the ones that bother you.

What "completely" doesn't cover

• The red spell-check underline — that's a separate, per-app option under Edit → Spelling and Grammar → Check Spelling While Typing. Turn it off per app if you want no marks at all.
• Per-app overrides — TextEdit and a few others keep their own Edit → Substitutions menu that can re-enable smart quotes locally.
• Your other devices — an iPhone or iPad has its own autocorrect setting; this change stays on the Mac.

Want just one piece gone rather than the lot? See how to disable the double-space period on Mac for the single most-hated one on its own.