Techniquest in Cardiff Bay will receive £3 million from the UK government to help it bring science to new audiences.
The centre is one of six in the UK to get a share of the Inspiring Science Fund - a £13 million scheme by Wellcome and the Department for Business, Energy and Industrial Strategy.
CEO Lesley Kirkpatrick said she was "over the moon" to receive the funding.
The centre's plans "to make science accessible to all" can now progress in earnest, she said.
Techniquest plans to develop a new STEM (science, technology, engineering and mathematics) hub to connect with new audiences who do not usually engage in science learning.
Secretary of State for Wales Alun Cairns said he could "not think of a worthier recipient" for the funding.
"The centre is home to many fond memories of children and adults in South Wales and further afield," he said.