Generally, for someone (who is not a director) whose only source of income relates to employment income taxed under PAYE system or if they have other income which is less than €3175 for a year and it is coded into their tax credit certificate, it is not compulsory to complete a tax return. Revenue can however request that someone in this situation complete and submit a form 12 tax return and in this case, yes you will be required to complete it. Otherwise, it is not compulsory! It is also possible to request a balancing statement from Revenue, without completing a Form 12 by registering with PAYE Anytime on revenue website.