If you’re a grandparent wondering whether you can pay into a grandchild’s Junior ISA, the short answer is yes, but with an important catch: you can’t open one yourself, and you can’t manage it either. That distinction trips up a lot of people, and it’s one of the most common questions we see asked about Junior ISAs here at the Children’s ISA. 

So if you’re a grandparent, here’s what you need to know. 

Who can actually open a Junior ISA?

Only a parent or legal guardian can open a Junior ISA (JISA) for a child. Whoever opens the account becomes the “registered contact,” which means they’re the one who manages it, chooses how it’s invested (for a stocks and shares JISA, which is what we offer here at the Children’s ISA), and makes decisions on the child’s behalf until they turn 18.

Grandparents don’t have this option. Even if you’re the one funding most of the account, and we tend to find that grandparents are key contributors to a Junior ISA, you can’t be the registered contact, and you can’t open the JISA in the first place. This responsibility falls exclusively within the purview of the child’s parents. 

So can grandparents pay into a Junior ISA?

Yes. Once a parent or guardian has opened the account, anyone can contribute, including grandparents, aunts, uncles, family friends, and godparents. There’s no restriction on who’s allowed to pay money in, only on who can open and run the account.

This is really the key thing to understand: contributing and controlling are two separate roles. You can absolutely be a major contributor to your grandchild’s JISA without ever having any say over how it’s managed.

How much can a grandparent contribute?

There’s no separate allowance for grandparents. All contributions, from parents, grandparents, and anyone else, count toward one combined annual limit per child.

For the 2026/27 tax year, that limit is £9,000, and it’s set to stay at £9,000 through to the end of the 2030/31 tax year following the 2025 Autumn Budget. This allowance can be split across a cash JISA and a stocks and shares JISA in any combination, but the combined total across both can’t exceed £9,000 in a tax year.

So if parents have already paid in £6,000, grandparents (and anyone else) can only add a further £3,000 before the annual limit is reached. It’s worth checking with the parents periodically so contributions don’t accidentally tip over the cap.

How grandparents actually pay in

Once the account is open, contributing is usually straightforward:

• Bank transfer or standing order directly into the JISA, using the details the parent provides.

• Direct payment through the provider’s website or app, if the provider allows third-party contributions without needing the registered contact to process it manually.

• Setting up a regular standing order is a popular option for grandparents who want to contribute steadily — for example, a monthly amount instead of one-off gifts.

What can’t grandparents do?

To be clear about the boundaries: opening and managing the account is strictly a parent or guardian’s job, known as the ‘registered contact.’ That means grandparents have no access to statements, no ability to switch investments, and no login of their own. A grandparent could only become the registered contact if they became the legal guardian of the grandchild. 

A note on gifting and inheritance tax

Contributions grandparents make to a Junior ISA count as gifts for inheritance tax purposes. Most grandparents won’t need to worry about this, but it’s worth knowing the basics: each grandparent has a £3,000 annual gift allowance that falls outside their estate immediately, and small gifts of up to £250 per person, per year are also exempt. Larger gifts are treated as ‘potentially exempt transfers,’ meaning they fall outside your estate after seven years, provided you live that long. This isn’t tax advice, though if you’re contributing significant sums or thinking about estate planning more broadly, it’s worth speaking to a financial adviser.

A popular alternative to traditional gifts

Many grandparents use JISA contributions as a replacement for, or an addition to, birthday and Christmas presents. A £50 or £100 contribution a few times a year adds up significantly by the time a grandchild turns 18, especially with investment growth in a stocks and shares JISA. Of course, investments can go up as well as down but, over the long term investments tend to outpace cash over the long term, especially during periods of high inflation. 

Grandparents can’t open a Junior ISA, but they can absolutely pay into one once a parent has set it up. Contributions simply count toward the same £9,000 annual limit shared by everyone paying in, so it’s worth a quick conversation with the parents to make sure contributions are coordinated and the allowance isn’t accidentally exceeded.