Names begining with " St. " are listed under the first
letter following the prefix
e.g. St.Clair is under "C", St.Paul under "P", etc.
| Family Name | Gaelic Equivalent | Original language | English Translation |
| Salmon(d) | Ó Bradáin | Optima sapientia probitas. | Probity is the best wisdom. |
| Sarsfield | Sáirséil | Virtus non vertitur. | Virtue not changed. |
| Saunders | Mac Sandair | Nil conscire sibi. | To have a conscience free from guilt. |
| Savage | Sabaois | A te pro te. | From thee, for thee. |
| Scanlon | (Ó) Mac Scannláin | Naom colmcille agus an t-angeal. | St. Columbkille and the angle. |
| Scott | Albanac | Patriae fidus. | Faithful to my country. |
| Scully | Ó Scolaí | Sine labe resurgens. | To rise again. |
| Sexton | Ó Seasnáin | - | - |
| Shanahan | Ó Seancáin | Nec elatus nec dejectus. | Neither overjoyed, nor dejected. |
| Shanley | Mac Seanlaoic | Pro patria et religione. | For country and religion. |
| Sharkey | Ó Searcaig | Sed contra audentior. | Courage, against opposition. |
| Sharp(e) | Ó Géaráin | Pro mitra coronam. | A crown for a mitre. |
| O'Shaughnessy | Ó Seacnasaig | Díleas go deo. | Faithful forever. |
| O'Shaughnessy | Ó Seacnasaig | Fugit hora. | The hour flies. |
| Shaw | Seac | Te ipsum nosce. | Know thyself. |
| O'Shea | Ó Seagda | Vincit veritas. | Truth prevails. |
| Sheehan | Ó Siocáin | Semper paratus. | Always prepared. |
| Sheehy | Mac Sitig | Certavi et vici. | I have fought and conquered. |
| Sheridan | Ó Sirideain | Cervus lacessitus leo. | The stag at bay becomes a lion. |
| Sherlock | Scorlóg | Pres pour mon pais. | Ready for my country. |
| Shields | Ó Siall | Omni solum forti patria. | Every land is a brave man's country. |
| Shortall | Soirtéil | Certavi et vici. | I have fought and conquered. |
| Simpson | Mac Sim | Virtute et valore. | By virtue and valour. |
| Sinnott | Sionóid | Sine macula. | Without spot. |
| Skerrett | Sciréid | Primus ultimusque in acie. | First and last in battle. |
| Slattery | Ó Slatara | Crescit sub pondere virtus. | Virtue thrives beneath oppression. |
| Sloane | Ó Sluáin | Vi et virtute. | By strength and valour. |
| Sackvill(e) | - | Aut nunquam tentes, aut perfice. | Either do not attempt, or complete. |
| Sackville | - | Patriae inflici fidelis. | Faithful to my unhappy country. |
| Sage | - | Non sibi. | Not for himself. |
| De Salis | - | Pro Deo, rege, et patria. | For God, king, and country. |
| Salmon | - | Dum spiro spero. | While I breath I hope. |
| Salomons | - | Deo adjuvante. | With God assisting. |
| Sanderson | - | Toujours propice. | Always propitious. |
| Sandford | - | Cor unum via una. | One heart one way. |
| Sandford | - | Nec temere nec timide. | Neither rashly nor timidly. |
| Sandilands | - | Spero meliora. | I hope for better things. |
| Sanford | - | Ferme en foy. | Strong in faith. |
| Sarkville | - | Jour de ma vi. | Day of my life. |
| Saunders | - | Spec mea in Deo. | God is my hope. |
| Savage | - | - | Ware the horn. |
| Savage | - | Fortis atque fidelis. | Brave and faithful. |
| Savile | - | Nil conscire sibi. | To have a conscience free from guilt. |
| Savory | - | Esse quam videri. | To be, rather than to seem. |
| Sayer | - | Misneac. | Bear and forbear. |
| Sayle | - | - | Who most has served is greatest. |
| Scarta | - | Volando, reptilia sperno. | Flying, I despise reptiles. |
| Scarth | - | Volando, reptilia sperno. | Flying, I despise reptiles. |
| Scott | - | - | Doe weel and let them say. |
| Scott | - | - | Fear to transgress. |
| Scott | - | - | Free. |
| Scott | - | - | Trustie and true. |
| Scott | - | - | Watch weel. |
| Scott | - | Amo probos. | Love proved. |
| Scott | - | Fidelitas vincit. | Faithfulness conquers. |
| Scott | - | Pro patria. | For my country. |
| Scras | - | Volando, reptilia sperno. | Flying, I despise reptiles. |
| Scrase | - | Volando, reptilia sperno. | Flying, I despise reptiles. |
| Sellar | - | Confido | I confide. |
| Sempill | - | - | Keep tryst. |
| Semple | - | - | In loyalty |
| Serjeantson | - | Pro aris et focis. | For our altars and our home. |
| Seton | - | - | Forward ours. |
| Seton | - | - | Hazard warily. |
| Seymour | - | Fide et amore. | Faith and love. |
| Seys | - | Crescit sub pondere virtus. Virtue thrives beneath oppression. | - |
| Shank | - | Spero. | I hope. |
| Sharp | - | Dum spiro spero. | While I breath I hope. |
| Sharpe | - | En Dieu est tout. | In God is all. |
| Shaw | - | - | I mean well. |
| Shaw | - | Sans changer. | Without changing. |
| Shaw | - | Vincit amor patriae. | To love my country. |
| Shaw | - | Vincit qui patitur. | The one who is patient wins. |
| Shearman | - | Fide et amore. | Faith and love. |
| (O') Shee | - | Vincit veritas. | Truth conquers. |
| (O') Sheil | - | Omne solum forti patria. | Every sail to a brave man in his country first. |
| Shelley | - | Comme je trouve. | As I find it. |
| Shelmerdine | - | Nil desperandum. | Never dispair. |
| Sheppard | - | Fide et virtute. | By fidelity and valour. |
| Sherburne | - | Nec temere nec timide. | Neither rashly nor timidly. |
| Sheriff | - | Esse quam videri. | To be, rather than to seem. |
| Sherrif | - | Esse quam videri. | To be, rather than to seem. |
| Shirley | - | Honor virtutes praemium. | Honor is the reward of valour. |
| Shorrock | - | Perseverando. | By perservering. |
| Sibbald | - | Ora et labora. | Pray and labour. |
| Siborne | - | Sine macula. | Without stain. |
| Sibthorp | - | Nil conscire sibi. | To have a conscience free from guilt. |
| Siddons | - | - | Thus thou must do if thou have it. |
| Sidley | - | Deo patria tibi. | For God, country, and yourself. |
| Sillifant | - | Mens conscia recti. | A mind conscious of rectitude. |
| Simeon | - | Nec temere nec timide. | Neither rashly nor timidly. |
| Simons | - | - | Upward. |
| Simpson | - | Nil desperandum. | Never dispair. |
| Sinclair | - | - | Commit thy work to God. |
| Sinclair | - | - | Fear God and live. |
| Sinclair | - | - | Fight. |
| Sisson | - | - | Hope for the best. |
| Sitlington | - | - | Have mercy on us, good Lord. |
| Skinner | - | Nunquam non paratus. | Never unprepared. |
| Skipton | - | Pro patria. | For my country. |
| Slade | - | Fidus et audax. | Faithful and bold. |
| Sladen | - | Vive ut vivas. | Live that you may live forever. |
| Slater | - | Crescit sub pondere virtus. Virtue thrives beneath oppression. | - |
| Sligo | - | Vincit omnia virtus. | Virtue conquers all. |
| Sources: | |
| Irish Family Mottoes | "The General Armory of England, Scotland, Ireland, and Wales." |
| By Tomás ó Baoill | by Sir John Bernard Burke |