| School | Roll number | Total (latest year) | Latest average class size | Largest class | Classes 30+ |
|---|---|---|---|---|---|
| SCOIL BHRIDE NS | 19747M | 727 | 19.86 | 23 | 0 |
| Holy Family Senior School | 20480F | 644 | 23.41 | 26 | 0 |
| Holy Family Junior School | 20270R | 599 | 23.40 | 26 | 0 |
| SCOIL PHADRAIG | 17827A | 521 | 21.87 | 26 | 0 |
| PRESENTATION PRIMARY SCHOOL | 15556I | 496 | 22.48 | 29 | 0 |
| Portlaoise Educate Together NS | 20347D | 457 | 23.42 | 27 | 0 |
| SCOIL CHOMHGAIN NAOFA | 17617M | 380 | 23.12 | 27 | 0 |
| S N NAOMH EOIN | 18641O | 374 | 23.38 | 28 | 0 |
| GAELSCOIL PHORT LAOISE | 20081O | 369 | 22.69 | 28 | 0 |
| St Coleman's National School | 20353V | 318 | 23.54 | 30 | 1 |
| SCOIL MHUIRE | 19750B | 269 | 22.27 | 31 | 1 |
| SCOIL BHRIDE | 20071L | 244 | 23.20 | 30 | 1 |
| ST JOSEPHS GIRLS N.S. | 07183W | 230 | 19.17 | 26 | 0 |
| SCOIL PADRAIG | 17064U | 218 | 23.56 | 30 | 1 |
| FRAOCH MOR N S | 18150S | 212 | 26.50 | 31 | 1 |
| RAITHIN AN UISCE N S | 17604D | 211 | 25.62 | 31 | 1 |
| S N BAILE FINN | 15537E | 208 | 22.44 | 27 | 0 |
| EMO MIXED N S | 13643Q | 207 | 24.38 | 27 | 0 |
| NA CARRAIGE N S | 18206T | 204 | 24.75 | 28 | 0 |
| RATH MIXED N S | 13741Q | 194 | 22.75 | 24 | 0 |
| MHUIRE FATIMA N S | 18368W | 193 | 22.62 | 26 | 0 |
| OUR LADYS MEADOW NATIONAL SCHOO | 20065Q | 192 | 22.50 | 29 | 0 |
| MOUNTMELLICK BOYS N S | 16070K | 187 | 15.91 | 24 | 0 |
| Ballyroan Primary School | 20485P | 177 | 24.43 | 29 | 0 |
| TOBAR AN LEINN | 16667W | 167 | 25.83 | 32 | 3 |
| CAMROSS N S | 15933M | 156 | 26.00 | 29 | 0 |
| KILADOOLEY MIXED N S | 12692B | 132 | 26.40 | 32 | 2 |
| SCOIL BHRIDE | 20118L | 127 | 21.17 | 27 | 0 |
| BALLYADAMS N S | 16617H | 111 | 24.75 | 26 | 0 |
| CASTLETOWN N.S | 20169F | 111 | 19.80 | 25 | 0 |
| ST FINTANS N S | 07636K | 108 | 19.20 | 22 | 0 |
| Scoil Tíghearnach Naofa | 19791P | 108 | 18.00 | 24 | 0 |
| SHANGANAMORE N S | 00892Q | 106 | 18.80 | 23 | 0 |
| SCOIL ABBAIN CILLIN | 17557U | 99 | 19.80 | 31 | 1 |
| BALLINAKILL MIXED N S | 00895W | 98 | 24.50 | 29 | 0 |
| MARYBORO N S | 14838N | 96 | 24.00 | 28 | 0 |
| SCOIL BHRIDE | 13343E | 95 | 19.00 | 23 | 0 |
| St Josephs National School | 07442U | 95 | 19.50 | 27 | 0 |
| Barr na Sruthan N S | 18294T | 91 | 19.75 | 24 | 0 |
| CLUAIN EIDHNEACH N S | 18166K | 89 | 19.25 | 20 | 0 |
| NAOMH PADRAIG N S | 18513F | 86 | 20.00 | 22 | 0 |
| ABBEYLEIX STH N S | 14260F | 84 | 21.00 | 24 | 0 |
| Scoil Náisiúnta Cúil an tSúdaire 2 | 18203N | 84 | 21.00 | 27 | 0 |
| PADDOCK N S | 13173F | 80 | 20.00 | 23 | 0 |
| ROSENALLIS N S | 17493U | 75 | 15.75 | 23 | 0 |
| SCOIL NAOMH ABBAN | 17555Q | 73 | 22.33 | 23 | 0 |
| S N NAOMH COLMCILLE | 18780F | 71 | 17.75 | 22 | 0 |
| CLOCH AN TSIONNAIGH N S | 15562D | 64 | 21.33 | 25 | 0 |
| S N FIONNTAN NAOFA | 17489G | 60 | 18.00 | 26 | 0 |
| S N MOLAISE | 17695J | 58 | 19.33 | 23 | 0 |
| COSBY N S | 10544W | 57 | 19.00 | 29 | 0 |
| Scoil Mhuire Naofa Castlecuffe | 17883K | 53 | 15.67 | 18 | 0 |
| ARDLIOS N S | 18532J | 50 | 14.67 | 21 | 0 |
| GAELSCOIL AN TSLI DALA | 20224K | 49 | 19.50 | 22 | 0 |
| NAOMH PIUS X N S | 18433H | 49 | 16.33 | 19 | 0 |
| ST PAULS N S | 19369G | 41 | 20.50 | 24 | 0 |
| TRUMMERA N S | 15446B | 34 | 17.00 | 19 | 0 |
| RUSH HALL MIXED N S | 12231L | 30 | 15.00 | 16 | 0 |
| Scoil an Chroi Ro Naofa | 18014K | 29 | 14.50 | 17 | 0 |
| CILL AN IUBHAIR N S | 17084D | 23 | 11.50 | 12 | 0 |
| SCOIL MHUIRE MUIGHEO | 17271C | 22 | 11.00 | 13 | 0 |
| BHRIDE N S | 18265M | 13 | 6.50 | 8 | 0 |
| SCOIL MHUIRE | 17441B | 9 | 4.50 | 5 | 0 |