Can I wear a smart watch during the ACT?

I know that you can't bring a phone to the test, but I am wondering if I could wear my smart watch? It's the only watch I own and want to use it to help keep time for each section. I looked at the ACT website and didn't see any mention of watches.

No, you shouldn't wear your smartwatch to take the ACT. From the ACT website's list of prohibited behaviors at test centers:

"Using any electronic device at any time during testing or during break other than an approved calculator or watch. All other electronic devices, including cell phones and wearable devices, must be turned off and placed out of reach from the time you are admitted to test until you are dismissed after testing concludes."

Though smartwatches aren't mentioned specifically, they definitely count as "wearable devices," so you shouldn't be using yours during the test. There will be a clock in the testing room that you can consult periodically to make sure you're on track to finish each section.