Zir Ab (Persian: زيراب) may refer to:
- Zirab, a city in Mazardaran Province, Iran
- Zir Ab, Fars, a village in Fars Province, Iran
- Zir Ab, Khuzestan, a village in Khuzestan Province, Iran
- Zir Ab, Razavi Khorasan, a village in Razavi Khorasan Province, Iran
- Zir Ab (ruins), ruins in Isfahan Province, Iran
- Rizab, Bardaskan, in Khorasan, Iran