The canton Lillers has 22 communes.
| Code | Name | Population ▼ |
|---|---|---|
| 62516 | Lillers | 10 193 |
| 62502 | Lestrem | 5 009 |
| 62770 | Saint-Venant | 2 999 |
| 62188 | Burbure | 2 834 |
| 62023 | Allouagne | 2 823 |
| 62376 | Gonnehem | 2 525 |
| 62195 | Calonne-sur-la-Lys | 1 595 |
| 62620 | Norrent-Fontes | 1 381 |
| 62713 | Robecq | 1 328 |
| 62584 | Mont-Bernanchon | 1 317 |
| 62190 | Busnes | 1 243 |
| 62407 | Ham-en-Artois | 944 |
| 62328 | Ferfay | 861 |
| 62028 | Ames | 676 |
| 62747 | Saint-Floris | 618 |
| 62162 | Bourecq | 568 |
| 62049 | Auchy-au-Bois | 548 |
| 62286 | Ecquedecques | 511 |
| 62029 | Amettes | 469 |
| 62500 | Lespesses | 402 |
| 62508 | Lières | 335 |
| 62885 | Westrehem | 246 |