It has stores in Athlone, Mullingar, Tullamore and Portlaoise.
Apache Pizza says it's been impacted by a data breach.
The fast food chain, which has more than 150 outlets across the country including Athlone, Mullingar, Tullamore and Portlaoise, says it was notified of the breach on Wednesday.
It's confirmed customer's personal data may have been accessed by the hackers, although credit card details weren't compromised.
It's alerting customers of the breach.