| Portmarnock | |
| Native Name: | Port Mearnóg |
| Native Name Lang: | GA |
| Symbol: | rail |
| Symbol Location: | ie |
| Address: | Station Road, Portmarnock, County Dublin, D13 K726 |
| Country: | Ireland |
| Coordinates: | 53.4175°N -6.151°W |
| Structure: | At-grade |
| Platform: | 2 |
| Tracks: | 2 |
| Original: | Dublin and Drogheda Railway |
| Pregroup: | Northern Railway of Ireland |
| Postgroup: | GNRI |
| Prenational: | CIÉ Railways Division |
| Years: | 25 May 1844 |
| Events: | Station opens |
| Years1: | 10 April 2000 |
| Events1: | DART services commence |
| Code: | PMNCK |
| Owned: | Iarnród Éireann |
| Operator: | Iarnród Éireann |
| Zone: | Suburban 2 |
| Embedded: | |
Portmarnock railway station (Irish: Stáisiún Phort Mearnóg) serves Portmarnock in County Dublin.
The station opened on 25 May 1844.
The station is served by the DART and Commuter services. Enterprise services pass from Dublin Connolly en route via Drogheda, Dundalk, Newry, Portadown,, and Belfast Central. Connecting trains from Dublin Connolly link to Sligo, as well as Rosslare Europort and buses connect Dublin Connolly to Dublin Port for ferries to Holyhead for trains to, and London Euston.