Jersey politicians have voted in favour of the "20% means 20%" tax proposals by 38 votes to 10. The move will see a phasing out of exemptions and allowances for higher earners, who will pay more income tax under the plans.
Middle and lower income earners should see bills go down, the States said.
The plans are part of government efforts to make up a projected budget shortfall of �100m in States finances when corporation tax is abolished.
The abolition of corporation tax will see tax on corporate profits cut to zero for some firms and 10% for others as part of a States strategy to keep Jersey financially competitive.