Why interviewers ask this question
This question tests whether you can set a boundary or decline a request professionally when it genuinely was not the right call to say yes, whether due to capacity, quality, or misalignment with priorities. Interviewers are wary of candidates who agree to everything regardless of feasibility, since that often leads to missed deadlines or quietly dropped commitments later.
How to structure your answer using STAR
Choose a real example where saying no was the professionally correct choice, not simply avoiding extra work. Briefly explain the situation and the request, then focus the action on how you declined clearly and respectfully, explained your specific reasoning, and, ideally, offered an alternative or compromise where possible. Close with the result, showing the outcome was better than if you had said yes reluctantly.
A strong example answer
"A stakeholder asked my team to take on an additional urgent project mid-sprint, which would have meant either missing our existing commitment or delivering both poorly. I explained clearly that I could not commit to both without compromising quality on one, and offered two specific alternatives: deprioritising a lower-impact existing task to make room, or delaying the new request by one sprint. The stakeholder chose to deprioritise the lower-impact task, and both pieces of work were delivered properly rather than both being rushed."
Mistakes to avoid
Avoid an example that makes you sound rigid or unhelpful; the best answers show a considered, respectful decline with a genuine alternative offered, not a flat refusal. Avoid choosing an example where you said no simply to avoid extra effort rather than for a genuine capacity or quality reason.