For an Irish-resident individual, dividend income is generally taxable, with the final treatment depending on where the company is based, your tax residence and how the investment is held. Dividends from Irish companies may have dividend withholding tax deducted before payment, which can usually be taken into account against your Irish tax liability where the rules allow. Overseas dividends may also have foreign withholding tax, with treaty relief or a credit potentially available, subject to the relevant conditions. Check the current guidance on revenue.ie or speak to a qualified tax adviser, particularly if you receive significant foreign dividends or file a Form 11 return.