If you don’t have a specific professor in mind,
Open up a global ranking of universities, such as the Times Higher Education Ranking
Filter by the subject/department in which you want a research internship.
For me, the subject/department was Psychology back in 2021 when I did my undergrad in Psych, but if you don't know which subject or department you should do it in, and if you wanna use your RAship to get ahead in your career, I suggest working with a professor who researches a highly relevant topic. In August 2026, that topic is AI. Everyone is researching AI.
Also, business schools have professors have better industry connections than professors in other departments, which can put you ahead of other job applicants.
A helpful tip to choose a professor fit for your goals: Some people do RAships to get ahead in their career. In that case, it's better to work with a celebrity professor who is well known.
Some people do RAships because they deeply love the topic and they don't care if it's with a reputed professor or not.
In general, reputed professors and reputed universities would bring you better future opportunities.
For me, it was the website of the Psychology department of the University of Cambridge, https://www.psychol.cam.ac.uk/
Go through the faculty/lab list of the department to shortlist professors who study your research interest
For me, it was professors/labs who studied social-political psychology: https://www.psychol.cam.ac.uk/research/research-centres