A review of 70 studies looking at 200,000 children suggests parents who "buffer" children from negative experiences make them more vulnerable.
But children who have harsh or negative parents are most likely to be bullied, it finds.
Professor Dieter Wolke said everyone looked at schools, but his study says bullying really starts at home.
The University of Warwick-based psychology professor said he was expecting to find that children with the harshest parents were most likely to become prey to bullies.
But he said he was somewhat surprised to discover that children with over-protective parents were also at an increased risk of bullying.
Bullying was defined as repeated instances over a six-month period, rather than just one-off conflicts in the playground.
So the way a child reacts to an initial instance of bullying has repercussions for what the bullies do next. Once they have established who to target they increase their dominance by repeatedly victimising them.
The research, which covered a number of countries in Europe and the US, also found that children who were bullied by their siblings were more likely to be victims as well.