Names begining with " De " are listed under the first
letter following the prefix
e.g. De Jersey is under "J", De Courey under "C", etc.
| Family Name | Gaelic Equivalent | Original language | English Translation |
| Dale | - | Spectemur agendo. | Let us be judged by our actions. |
| Dalrymple | - | - | Be firm. |
| Dalton | Daltún | - | God is my defender. |
| Dalton | Daltún | Tristus et fidelis. | Sad and faithful. |
| Daly | Ó Dalaigh | Deo fidelis et patria. | Faithful to God and country. |
| Dalyell | - | - | I dare. |
| Dalyell | - | - | Right and reason. |
| Dalzell | - | - | I dare. |
| Dancer | - | Vincit qui patitur. | The one who is patient wins. |
| Daniel | - | Toujours pret. | Always ready. |
| Daniell | - | Pro fide et patria. | For faith and country. |
| Darbishire | - | Ubi amor ibi fides. | Where there is love, there is faith. |
| Darby | - | Spero meliora. | I hope for better things. |
| Darcy | Ó Dorchaidhe | Un Dieu un roi. | On God one king. |
| Darely | - | - | Dare. |
| Darley | - | Per mare per terras. | By land and sea. |
| Dargan | Ó Deargáin | Pro Deo et patria. | For God and country. |
| Darlington | - | Cruce dum spero fido. | While I breath I hope. |
| Darroch | - | - | Be watchful. |
| Dauglish | - | - | Be hardy. |
| Davenport | - | - | Fear God, honor the King. |
| Davies | - | Esse quam videri. | To be, rather than to seem. |
| Davies | - | Heb Dduw heb ddin a Duw a digon. | Without God, without anything, God is enough. |
| Davies | - | Sic itir ad astra. | This is the way of the stars. |
| Davis | Daibis | - | I will. |
| Davis | Daibis | Virtute et fidelitate. | By valour and fidelity. |
| Davoran | Ó Duibhdabhoireann | Nunquam non paratus. | Never unprepared. |
| Davys | - | - | Forget not. |
| Dawes | - | - | Fear not. |
| Dawson | Mac Daibí | Manus hoec inimica tyrannis. | This hand is hostile to tyrants. |
| Dawson | Mac Daibí | Perseverando. | By perservering. |
| Dawson | Mac Daibí | Toujours propice. | Always propitious. |
| Dawson | Mac Daibí | Virtute non verbis. | Deeds not words. |
| Day | - | Sic itir ad astra. | This is the way of the stars. |
| Dayman | - | Toujours prest | Always nimble. |
| O'Dea | Ó Deághaidh | Sic itir ad astra. | This is the way of the stars. |
| Deacon | - | In utrumque paratus. | Prepared for both. |
| Deakin | - | Fidelitas vincit. | Faithfulness conquers. |
| Deane | Ó Déin | Aarte vel marte. | By art, or by work. |
| Deane | Ó Déin | Forti et fideli nihil difficle. | To the brave and faithful man nothing is difficult. |
| Deane | Ó Déin | Fortiter et fideliter. | Boldly and faithfully. |
| Dease | - | Toujours pret. | Always ready. |
| Deasy | Deiseac | Toujours pret. | Always ready. |
| Delacourt | - | Fortis et fidelis. | Brave and faithful. |
| Delaney | Ó Dubhshláinte | Depressus tamen extollor. | - |
| Delap | - | Merito. | With merit. |
| Deline | - | Esse quam videri. | To be, rather than to seem. |
| Dempsey | Ó Diomasaig | Elatium a Deo non deprimat. | Upheld by God I am not depressed. |
| Dennehy | Ó Duineachdha | Labore et honore. | Labour with honour. |
| Dennis | - | Dieu a la mer. | God is the sea. |
| Mac Dermot | Mac Diarmada | Honor virtutes praemium. | Honor is the reward of valour. |
| Mc Dermott | Mac Diarmada | Honor et virtus. | Honour and virtue. |
| Mc Dermott | Mac Diarmada | Honor probataque virtus. | Honour and approved valour. |
| Desmond | Ó Deasunaig | Virtutis praemium honore. | Honour is the reward of virtue. |
| Devaney | Ó Duibheamhna | Non sibi solum. | Not alone for oneself. |
| Deveroux | Déabruis | Bassis virtutum constantia. | Constancy is the foundation of all virtue. |
| Devlin | Ó Doibhilin | Crux me stella. | The cross is my star. |
| Dewhurst | - | Spec mea in Deo. | God is my hope. |
| Diamond | - | Miseris succurrere disco. | I learn to succour the unfortunate. |
| Dicey | - | Fide et amore. | Faith and love. |
| Dick | - | Semper fidelis. | Always faithful. |
| Dick | - | Virtute. | By virtue. |
| Dickin | - | Vincit veritas. | Truth conquers. |
| Dickins | - | Semper fidelis. | Always faithful. |
| Dickson | - | Cubo sed curo. | I rest but care. |
| Dickson | - | Fortes fortuna juvat. | Fortune favours the bold. |
| Dillon | Ó Duilleain | Dum spiro spero. | While I breath I hope. |
| Dinneen | Ó Duinnín | Toujours pret. | Always ready. |
| Dirom | - | - | Be sure. |
| Disney | - | Vincit qui patitur. | The one who is patient wins. |
| Dixon | Mac Riocairo | - | Peace. |
| Dixon | Mac Riocairo | Cubo sed curo. | I rest but care. |
| Dixon | Mac Riocairo | Fortes fortuna juvat. | Fortune favours the bold. |
| Dobbin | - | Re et merito. | By reality and merit. |
| Dockrell | - | Semper eadem. | Always the same. |
| Dodd | Doda | In copia cautus. | Careful and plenty. |
| Doherty | Ó Dochartaigh | Ár ndútcas. | Our inheritance. |
| Dolan | Ó Dubhhláin | Virtute et fidelis. | By faith and virtue. |
| Dolling | - | Spero. | I hope. |
| Domenichetti | - | Nunquam non paratus. | Never unprepared. |
| Mc Donagh | Mac Donnchadha | Virtus gloria merces. | Glory is the reward of virtue. |
| Mac Donald | Mac Dónaill | - | My hope is constant in thee. |
| Mc Donald | Mac Dónaill | Per mare per terras. | Over land and sea. |
| Mac Donald | Mac Dónaill | Pro patria. | For my country. |
| Donaldson | - | - | My hope is constant. |
| Donaldson | - | Si Deus vobiscum qui contra nos. | If God be with us, who can be against us. |
| O'Donavan | Ó Donndubháin | Vir super hostem. | A man above an enemy. |
| Donegan | Ó Donnagáin | Virtus non vertitur. | Virtue does not turn. |
| Donelan | Ó Domhnalláin | Omni violentia major. | Greater than all violence. |
| Mac Donell | Mac Domhnaill | Per mare per terras. | By land and sea. |
| Mac Dongall | - | - | Fear God. |
| Donkin | - | Disce pati. | Learn to endure. |
| Donlevy | Mac Duinnshléibhe | Merito. | With merit. |
| O'Donnell | Ó Domhnaill | In hoc signo vinces. | Under this sign you shall conquer. |
| Mc Donnell | Mac Domhnaill | Sero sed serio. | Late but in earnest. |
| Mc Donnell | Mac Domhnaill | Toujours pret. | Always ready. |
| Donnelly | Ó Donnghaile | Lám bearg éirann | The red hand of Ireland. |
| Donnellan | Ó Domhnalláin | Omni violentia major. | Greater than all violence. |
| Donoghue | Ó Donnchadha | Nunquam non paratus. | Never unprepared. |
| O' Donovan | Ó Donndubháin | Crom a boo. | Crom defying. |
| Donovan | Ó Donndubháin | Giolla ar a'namuid abú. | A youth over his enemies defying. |
| Doolan | Ó Dúlainn | Fortis et egregius. | Brave and distinguished. |
| Dooley | Ó Duighlaich | Fortes fortuna juvat. | Fortune favours the bold. |
| Doran | Ó Deoráin | Spec anchora vitae. | Hope is the anchor of life. |
| Douglas | Mac Dúglais | - | Do or die. |
| Douglas | Mac Dúglais | - | Forward. |
| Douglas | Mac Dúglais | - | God for us. |
| Douglas | Mac Dúglais | - | Lock sicker. |
| Douglas | Mac Dúglais | Fortis et fidelis. | Brave and faithful. |
| Douglas | Mac Dúglais | Gluaiseact ar agaid. | Forward motion. |
| Douglas | Mac Dúglais | Pro patria. | For my country. |
| Douglas | Mac Dúglais | Spero. | I hope. |
| Douglas | Mac Dúglais | Sursum. | Upwards. |
| M'Dowall | - | Pro Deo, rege, et patria. | For God, king, and country. |
| M'Dowall | - | Sic itir ad astra. | This is the way of the stars. |
| M'Dowall | - | Victoria. | Victory. |
| O'Dowd | Ó Dubhda | Virtus ipsa suis firmissima nititur armis. | Bravery is best sustained by arms. |
| Mc Dowell | Mac Dugaill | Fortis in arduis. | Brave under difficulties. |
| Dowdal | Dúdul | Fidelis usque ad mortem. | Faithful even to death. |
| Dowine | - | - | Hold fast. |
| Dowling | Ó Dunlaing | Fortis et egregius. | Brave and distinguished. |
| Downfield | - | Virtute et labore. | By valour and exertion. |
| Downes | Ó Dubáin | Parle bien ou parle rien. | Speak well or say nothing. |
| Downey | Ó Dúnadhaigh | Lám láidir in uactar. | The strong hand uppermost. |
| Doyle | Ó Dubhghaill | braidimse neas. Fortitudine vincit. | He conquers by fortitude. |
| Doyne | - | Mullach a boo. | Victory for the Duns, or the inhabitants of the hills. |
| Drake | - | - | The eagle does not catch flies. |
| Drew | Ó Draoi | Drogo nomen et virtus arm dedid. | Drogo is my name, and valour gave me arms. |
| Drinkwater | - | Ne quid nimis. | Nothing too much. |
| O'Driscoll | Ó hEidirsceoil | dún an óir. | Fort of the gold. |
| Drummond | - | - | Gang warily. |
| Drummond | - | - | Have it all. |
| Drummond | - | - | Lord have mercy. |
| Drummond | - | Consequiter quodcunque petit. | He obtains whatever he seeks. |
| Drummond | - | Dominus providebit. | God will provide. |
| Drummond | - | Dum spiro spero. | While I breath I hope. |
| Drummond | - | Loyal aut mort. | Loyal to the death. |
| Drummond | - | Per mare per terras. | By land and sea. |
| Drumson | - | Spectemur agendo. | Let us be judged by our actions. |
| Duckett | - | Spectemur agendo. | Let us be judged by our actions. |
| Dudgeon | - | - | With heart and hand. |
| Duff | Ó Duib | - | Be true and ye shall never rue. |
| Duff | Ó Duib | - | Kind heart. |
| Duff | Ó Duib | Deus juvat. | God assists. |
| Duffield | - | Semper fidelis. | Always faithful. |
| Duffy | Ó Dufaig | Deo patria amicis. | To God, country and friends. |
| Duggan | Ó Dubhagáin | Virtute et valore. | By virtue and valour. |
| Duignan | Ó Duigeannáin | Historia magistra vitae. | Virtue in history. |
| Duke | - | Gradatum vincimus. | We conquer by degrees. |
| Dukinfield | - | Ubi amor ibi fides. | Where there is love, there is faith. |
| Dunbar | - | Disce pati. | Learn to endure. |
| Duncan | Ó Donnacáin | Dise pati. | Learn to endure. |
| Duncan | Ó Donnacáin | Perseverando. | By perservering. |
| Duncombe | - | Deo, regi, patriae | God, king, country. |
| Dundas | - | - | Live to live. |
| Dunlop | - | Merito. | With merit. |
| Dunne | Ó Doinn | Mullac abú. | Victory to the chief. |
| Dunphy | Ó Donnchadha | Generosa virtus nihil timet. | Generous valour fears nothing. |
| Dunscombe | - | Fidelitas vincit. | Faithfulness conquers. |
| Dupuis | - | - | Persevere. |
| Durham | - | Per mare per terras. | By land and sea. |
| Durkin | Mac Duarcain | Virtue et claritate. | By virtue and high repute. |
| O'Dwyer | Ó Duibhir | Virtus sola nobilitas. | Virtue is the only nobility. |
| Sources: | |
| Irish Family Mottoes | "The General Armory of England, Scotland, Ireland, and Wales." |
| By Tomás ó Baoill | by Sir John Bernard Burke |