I did Notion's full interview process earlier this year and wasn't sure what to expect from the behavioral side. Posting this because I couldn't find much specific to Notion before going in.
First thing: Notion does care about behavioral. It's not an afterthought tucked into 10 minutes of an otherwise technical round. I had at least two rounds that were explicitly focused on past behavior and how I work. One with a hiring manager, one with a cross-functional partner.
Questions I was asked, roughly paraphrased: Tell me about a time you had to make a significant product or technical decision with incomplete information. What did you decide and what happened? Describe a project where you disagreed with the direction the team was taking. How did you handle it? Tell me about a time you had to simplify something that had gotten too complicated. (This one felt very Notion-specific.) Walk me through a time you failed to deliver something on the timeline you committed to. What changed and what did you do? How do you decide what NOT to work on?
That last one came up in two different rounds with different interviewers, which tells me it's probably intentional. Notion is famously opinionated about taste and restraint. The product is deliberately simple in ways that required saying no to a lot.
What they seem to care about. Good judgment under ambiguity. Clarity of thinking. Collaboration without being conflict-avoidant. They want to see that you have opinions and can back them up. At the same time, they're not looking for lone wolves.
What worked for me. Being specific. "The team decided X and I had concerns about Y, so I wrote a short doc with three alternatives and we picked Z" is so much better than vague answers about "communicating effectively." Notion is a doc-heavy culture. Showing you think in structured writing seems to land.
One round was noticeably more culture-fit oriented. Felt like they were checking whether I'd be someone they wanted to be in a room with long-term, not just whether I could do the job.