Junior ISA Explained: How the JISA Works and Who It Suits

A Junior ISA is a long-term, tax-free account for a child who is under 18 and living in the UK. There are two types, and a child can hold one of each at the same time:

• Cash Junior ISA — works like a tax-free savings account, paying interest with no tax to pay.
• Stocks and shares Junior ISA — the money is invested in funds, shares or other assets, with any growth and income free of tax.

The total paid across both types in a tax year cannot exceed the annual allowance. Over a horizon that can stretch to 18 years, the choice between cash and investments is significant: cash offers certainty but may lose value in real terms to inflation, while investing carries more short-term ups and downs but has historically offered more growth over long periods. The trade-off is the same one we cover in our article on cash ISA versus stocks and shares ISA, and the mechanics of the invested version mirror those in our stocks and shares ISA guide.

For the 2026/27 tax year the Junior ISA allowance is £9,000 per child. Key points:

• The allowance runs each tax year (6 April to 5 April) and cannot be carried forward — if you do not use it, it is lost.
• The £9,000 can be split in any proportion between the cash and stocks and shares JISA.
• It is completely separate from any adult's £20,000 ISA allowance, so paying into a child's JISA does not reduce your own tax-free room.

Because the money is locked away until the child turns 18, a JISA is best thought of as a genuinely long-term commitment rather than an accessible savings account.

A Junior ISA must be opened by a parent or legal guardian, who becomes the "registered contact" responsible for managing the account. But once it is open, anyone can contribute — grandparents, other relatives and family friends can all pay in, as long as the combined total stays within the £9,000 annual limit. This makes a JISA a straightforward way for a wider family to club together for a child's future, and it can also form part of a broader plan for gifting money to family. A child can also hold a JISA transferred from an old Child Trust Fund.

Everything inside a Junior ISA grows free of UK income tax and capital gains tax, and there is no tax to pay when the child accesses the money at 18. One particular advantage is worth highlighting for parents. Normally, if a parent gives a child money that generates more than £100 of income a year in an ordinary account, that income is taxed as the parent's under the "parental settlement rule". Money held inside a Junior ISA is not caught by that rule, so a parent can fund a JISA without worrying about it — a benefit that ordinary children's savings accounts and bare trusts do not share to the same extent. This tax-free wrapper sits alongside the wider set of allowances explained in our guide to tax efficient investing in the UK.

Control of the account shifts in two stages. From age 16, the child can take over managing the JISA as the registered contact if they wish, but they still cannot withdraw the money. At age 18, the Junior ISA automatically converts into an adult ISA, the money becomes legally theirs to do with as they choose, and they gain full access. For some families this is a positive — an 18-year-old inherits a tax-free ISA and the good habit of saving. For others it prompts a conversation about readiness, since there is no way to restrict access once the child reaches 18. It is worth being comfortable with that feature before you commit.

A Junior ISA is one of the simplest tax-efficient ways to save for a child, but it is rarely the whole picture. Grandparents thinking about passing wealth down may combine JISA contributions with other allowances, and HMRC's guidance on Junior Individual Savings Accounts sets out the current rules in full. Where larger sums or inheritance planning are involved, a JISA often sits alongside pensions, trusts and gifting strategies — and joining those together is where regulated advice can help.