| Arrondissement of Ath | |
| Native Name: | French: Arrondissement d'Ath |
| Type: | Arrondissement |
| Coordinates: | 50.6°N 3.75°W |
| Subdivision Type: | Country |
| Subdivision Name: |  Belgium |
| Subdivision Type1: | Region |
| Subdivision Type2: | Province |
| Parts Type: | Municipalities |
| Parts Style: | para |
| P1: | 11 |
| Unit Pref: | Metric |
| Area Total Km2: | 667.94 |
| Population Density Km2: | auto |
| Timezone1: | CET |
| Utc Offset1: | +1 |
| Timezone1 Dst: | CEST |
| Utc Offset1 Dst: | +2 |
The Arrondissement of Ath (French: Arrondissement d'Ath; Dutch; Flemish: Arrondissement Aat) is one of the seven administrative arrondissements in the Walloon province of Hainaut, Belgium. It is not a judicial arrondissement. Two of its municipalities, Brugelette and Chièvres, are part of the Judicial Arrondissement of Mons, while the others are part of the Judicial Arrondissement of Tournai.[1]
The Administrative Arrondissement of Ath consists of the following municipalities:
The three municipalities of the Arrondissement of Soignies (Enghien, Lessines and Silly) are integrated into the Arrondissement of Ath on January 1, 2019.