I had no payroll q3 2021. Do I still have to file a quarterly taxes?

Hi there, @flynaround.

Yes, you still need to file even if you have no payroll for the quarter. According to the IRS, any person or business that pays wages to an employee must file a Form 941 each quarter and must continue to do so even if there are no employees during some of the quarters.

Seasonal employers who aren't paying employee wages during one or more quarters, employers of household employees, and employers of agricultural employees are not required to file. 

You'll want to check out this article from the IRS: https://www.irs.gov/instructions/i941.

Read through this article to learn more about completing your tax setup before paying and filing your payroll taxes online: Pay and file payroll taxes in Quickbooks Online. 

Let me know if you need more help in paying and filing payroll taxes. I'm always around to share some more. Take care!