This question gets asked in every interview. Most candidates either lie ("seeking new growth opportunities") or overshare ("my manager was impossible"). Both signal something off.
The structure that works:
Step 1. Acknowledge what was good. "I learned a lot in my time at [company], particularly [specific skill or accomplishment]." This shows you can leave well.
Step 2. Name the gap honestly, without bitterness. "What I'm looking for next is [specific thing, scope, ownership, type of problem, growth path] that I don't see a clear path to in my current role." Specific is critical. "More growth" is meaningless. "Owning a P&L" or "leading product strategy directly" lands.
Step 3. Connect to their role. "From what I've read about [their role/company], it looks like that opportunity is here in [specific way]." Shows you've thought about why their role specifically.
What to avoid: bad-mouthing former managers, vague "personal reasons," lying about the timeline, blaming external circumstances. Hiring managers can spot all of these.
The honest version is almost always more credible than the polished version. Just make sure your honest answer doesn't include emotional bitterness, keep it about scope, growth, or fit.
— Dr. Hosney Adel