What is the 3-month deadline for employment tribunal claims?

The 3-month deadline is strict and almost never extended. If you miss it, you cannot make a tribunal claim (with rare exceptions). This is one of the most important dates to remember.

• Unfair dismissal: From the date you were dismissed (last day of work, not end of notice period)
• Discrimination: From the date the discrimination happened (or last act of discrimination)
• Ongoing discrimination: From the last act (so if harassment continues, the clock restarts each time)
• Wages not paid: From the date the payment was due

It's 3 months minus 1 day. Example: dismissed on 15 May → deadline is 14 August. No exceptions for weekends or bank holidays—14 August is the deadline whether it's a Saturday or not. You can contact ACAS any time up to and including 14 August. After midnight on 14 August, you've missed it.

Calling ACAS or submitting a form on their website counts. Sending ACAS an email or letter also counts if received before the deadline. But you must contact ACAS—contacting your employer, your union, or a solicitor does NOT stop the clock.

You lose the right to claim. Very rarely, a tribunal will allow a late claim if it was "not reasonably practicable" to meet the deadline—but being busy, forgetting, or relying on someone else to contact ACAS do NOT count as exceptions. Serious illness or emergency abroad might—but you'd need strong evidence.

Once you contact ACAS within the 3-month deadline, the clock stops. ACAS then has 1 month (or more if both sides agree) to try conciliation. After ACAS issues a certificate, you have another 3 months to submit your claim (ET1) to the tribunal.