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Ancillary activities

Many Leiden University employees engage in ancillary activities. The University stimulates such activities because we believe that the right place for a university is at the very heart of society. Ancillary activities bring together research, teaching and society. However, there are some limits on what is possible. Ancillary activities are subject to certain conditions, aimed primarily at guaranteeing transparency and avoiding conflicts of interests.

Please report all ancillary activities or any changes to these activities via Self Service. If you cannot access Self Service, please contact the PSSC Service Point.

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What constitutes ancillary work?

Ancillary activities include all paid and unpaid activities that a Leiden University employee engages in that are not related to his or her employment, whether these activities are carried out within working hours or outside these hours. When accepting ancillary work, please always make sure that these activities cannot harm the University or obstruct the proper performance of your duties. 


A University employee is a member of the local municipal council. The University wishes to commission a student accommodation unit at a specific location in the city. A local party is against this project and the University employee acts as spokesperson on behalf of this party. This situation clearly involves a conflict of interests.

Our researchers are often asked to act as advisers, for example in an institution for the settlement of investment disputes. Two Leiden researchers are members of the National Electoral Council, a government institution that monitors national elections. Another researcher investigates the incidence of violence in institutions for the blind and the deaf. These activities can easily be combined with their position at Leiden University. A conflict of interests might arise if Leiden University in some way becomes involved in a dispute or is the subject of a recommendation.

Another employee has a part-time position at the ICT department of Leiden University and also owns his own company. A proposal has to be written, and the employee wonders whether he can hire his own company for the job. The answer is ‘no’. You are not allowed to commission your own company to perform work related to your position at the University.

All activities must be notified

You are obliged to report all your ancillary activities and you require permission from the board of your faculty or unit. How do you know which ancillary activities you should discuss with your supervisor?

If you answer ‘yes’ to one of the questions below, you may have to discuss your ancillary activities with your supervisor.

  • Are there similarities between your ancillary activities and your work at the University?
  • Do you make use of the same network of persons, companies and/or institutions as in your position at the University?
  • Were you hired for these ancillary activities through/thanks to your position at the University?
  • Do you use information, knowledge or skills that you acquired in your position at the University?
  • Does the organisation or person for whom you perform these activities have a questionable reputation? 

What kind of ancillary activities do not have to be notified?

Compulsory notification does not apply if the ancillary activities in question:

  • Fall completely outside working hours and
  • Are unpaid and
  • Do not conflict with the exercise of your duties for the University and
  • Cannot harm the interests of the University

Registration and publication on the website

All ancillary work performed by Leiden University employees is recorded in a register. The record mentions the nature of the activities and the organisation for which they are carried out.

Once a year each employee is sent an e-mail asking him or her whether the registered ancillary activities still match the reality. You are personally responsible for publishing your ancillary activities on your profile page on the University website. In Self Service, you can report new ancillary activities or notify us that you have discontinued all or some of your ancillary activities. 

Ancillary activities and your P&D interview

The compatibility of your ancillary activities with your position at the University may be discussed in your P&D interview and you may have to reach an agreement with your supervisor on the conditions under which you are allowed to engage in these activities.


The rules on ancillary work are set out in the  Leiden University procedure for ancillary activities.

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