| 1 | John Sisk & Son | €715,500,000 | General Building, Civil Engineering | |
| 2 | Mercury | €600,000,000 | Mechanical & Electrical Engineering | |
| 3 | BAM Ireland | €560,000,000 | General Building, Civil Engineering | |
| 4 | Jones Engineering | €558,000,000 | Mechanical, Electrical, Process Engineering | |
| 5 | John Paul Construction | €420,000,000 | General Building, Civil Engineering | |
| 6 | PJ Hegarty & Sons UC | €340,000,000 | General Building, Civil Engineering | |
| 7 | Walls Construction | €303,000,000 | General Building, Main Contractor | |
| 8 | Kirby Group Engineering | €253,446,397 | Mechanical & Electrical Engineering | |
| 9 | Bennett | €250,000,000 | General Building, Main Contractor | |
| 10 | Winthrop | €234,122,533 | General Contractor | |
| 11 | Collen Construction | €222,000,000 | General Building | |
| 12 | JJ Rhatigan & Company | €202,200,000 | General Building, Main Contractor | |
| 13 | Suir Engineering | €175,000,000 | Mechanical & Electrical Engineering | |
| 14 | Murphy Ireland | €136,000,000 | General Building, Civil Engineering | |
| 15 | Designer Group | €125,426,000 | Mechanical & Electrical, Process Engineering | |
| 16 | Conack Construction Ltd | €122,000,000 | General Building | |
| 17 | Monami Construction | €106,000,000 | General Building | |
| 18 | Dornan | €105,000,000 | Mechanical & Electrical Engineering | |
| 19 | mac-group | €102,000,000 | General Building, Fit-outs | |
| 20 | Clancy | €95,721,578 | General Building | |
| 21 | Jons Civil Engineering Company Ltd | €92,000,000 | Civil Engineering | |
| 22 | SIAC Construction Group | €90,000,000 | General Building, Civil Engineering | |
| 23 | Radley Engineering Ltd | €87,012,069 | Mechanical Fabrication & Installation | |
| 24 | Duggan Brothers (Contractors) Ltd | €87,000,000 | General Building | |
| 25 | STS Group | €85,000,000 | Electrical Engineering | |
| 26 | Wills Bros | €82,000,000 | General Building | |
| 27 | Flynn | €77,505,447 | General Building | |
| 28 | Ardmac Group Ltd | €70,071,985 | General Building | |
| 29 | Stewart | €67,000,000 | General Building | |
| 30 | Purcell Construction | €65,900,000 | General Building | |
| 31 | MMD Construction (Cork) Ltd | €64,660,000 | General Building | |
| 32 | Vision Contracting Ltd | €63,500,000 | General Building | |
| 33 | BMD & Co Ltd | €62,700,000 | Mechanical, Electrical, Process Engineering | |
| 34 | Elliott Building & Civil Engineering Ltd | €60,000,000 | General Building, Civil Engineering | |
| 35 | Townmore | €56,000,000 | General Building | |
| 36 | Coffey Group | €52,700,000 | Civil Engineering | |
| 37 | Glan Agua MEIC | €51,751,663 | General Building, Civil Engineering | |
| 38 | Gem Group | €47,240,000 | General Building, Specialist | |
| 39 | MSL Engineering Ltd | €46,077,245 | Mechanical Engineering | |
| 40 | T&I Fitouts | €46,000,000 | Main Contractor, Fit-outs | |
| 41 | CJK Engineering | €44,546,326 | Mechanical & Electrical Engineering | |
| 42 | Clonmel Enterprises Ltd | €44,439,802 | General Building, Civil Engineering | |
| 43 | Leo Lynch | €44,270,000 | Mechanical & Electrical Engineering | |
| 44 | ABM Group | €44,000,000 | General Building, Civil Engineering | |
| 45 | Arkil Holding Ltd, (Arkil Ltd and Park Plant Hire Ltd) | €43,890,000 | Civil Engineering | |
| 46 | Ganson Building & Civil Engineering Contractors Ltd | €41,456,806 | General Building, CivilEngineering | |
| 47 | LMC Group Ltd | €41,160,000 | Mechanical & Electrical Contracting, Specialist Offsite Contractor | |
| 48 | Kilcawley Building & Civil Engineering (Sligo) Ltd | €40,000,000 | General Building, Civil Engineering | |
| 49 | Tritech Engineering | €36,000,000 | Mechanical & Electrical Engineering | |
