Can a landlord raise the rent during a fixed-term lease in Israel?

Not unilaterally. During a fixed-term lease, the rent can only be increased if the lease agreement explicitly provides for it — for example, a clause linking rent to the Israeli Consumer Price Index or providing for a fixed annual increase. If the lease is silent on rent increases, the agreed rent is fixed for the term. Unilateral rent increases during a fixed-term lease are not enforceable.