No, your landlord cannot freely increase your rent at will. Article 10 of Qatar's Property Leasing Law (Law No. 4 of 2008) clearly states that rent under leases already in force, or concluded after the law came into effect, may only be increased in accordance with rules, terms, and rates determined by the relevant authority. This means any rent hike must comply with officially set guidelines — a landlord cannot simply decide to raise the rent by an arbitrary amount.
In practice, Qatar has periodically issued ministerial decisions setting rent increase caps and freeze periods, so the permissible rate can change over time. It is worth checking the most current guidance from the Ministry of Justice or the Real Estate Lease Registration Office to confirm what rate applies at the time of your renewal.
If your landlord attempts to raise your rent outside of these official rules, you are not legally obliged to accept the increase. Always ensure any rent change is documented in a written addendum to your lease, and consider registering the updated lease as required under Article 3. If a dispute arises, the Rental Disputes Committee is the appropriate body to approach.
This is general legal information, not legal advice. For advice on your specific situation, consult a lawyer licensed in Qatar.