GRC manages and monitors risk day to day. Internal audit independently verifies that GRC's risk management is actually working — and it's deliberately kept separate so it can be objective about it. This split has a name: the Three Lines Model, and it's the standard way organizations structure risk oversight.
The Three Lines Model
Operational teams (the first line) own and manage risk directly — they implement controls day to day. GRC and risk/compliance functions (the second line) set frameworks, monitor risk, and support the first line. Internal audit (the third line) independently checks whether the first two lines are actually doing their job effectively, reporting directly to the board or an audit committee rather than to the teams it reviews.
Why the independence matters
A function generally can't objectively grade its own homework. If the same team that manages risk also audited its own controls, a serious gap could easily go unreported — not necessarily from dishonesty, just from the natural blind spots that come with being close to the work. Internal audit's whole value is coming from outside that loop.
Where the day-to-day work overlaps
In practice, both functions do similar things — reviewing policies, testing controls, examining audit evidence — which is why the two are often discussed together and why people move between them over a career. The difference is who they report to and why they're doing the review: GRC is trying to make the controls work; internal audit is verifying, independently, whether they actually do.
What this means for a career switcher
GRC Analyst and Internal/IT Auditor roles are close enough in skill set that they're worth considering together. Starting in GRC gives you hands-on exposure to building and running controls; moving into internal audit later adds the independent-verification skill set on top of that foundation. Either is a realistic entry point.