From Wednesday the point which workers pay the tax increases from £9,880 to £12,570.
Scottish Secretary Alister Jack said the changes would see 2.4 million workers north of the border “typically save around £330 a year”.
“We’re acutely aware of global issues raising the cost of living and this is part of a £37bn UK Government support package to ensure people keep more of their earnings,” the MP added.
But the move followed a controversial 1.25 percentage point increase in NI in April which came amid a string of other bill hikes, including a jump in the energy price gap.
Prime Minister Boris Johnson said his Government knew it was “rough for many families across the UK, but we want you to know that this Government is on your side”.
Across the UK, the Westminster government said, some 30 million will benefit from the tax cut.
It said the average bricklayer would save £218 a year, care workers £324, hairdressers £118, and nursery assistants £343.
Some 2.2 million across the UK will not pay the personal tax altogether, the Treasury said.
National insurance is a compulsory tax and state insurance system first introduced in 1911 by the National Insurance Act. It is calculated based on how much you earn before any tax or pension payments are deducted and whether these come above an earnings threshold
Whether or not you pay national insurance depends on your age, circumstances and how much you earn, but the mandatory payments on earnings go toward your state pension and entitle you to other benefits, such as Maternity Allowance.