Like the Student Council, the National Junior Honor Society (NJHS) provides the leadership in promoting the goals of Saint Brendan School. It is limited to Grade 8 students with induction of new members taking place during Catholic Schools Week.

The following is the established criteria for selection to the Saint Brendan National Junior Honor Society based on the guidelines issued by the National Council of the NJHS:

1. Membership is an honor bestowed upon a student in grade 8.
2. Candidates must have been in attendance in Saint Brendan School for at least two years.
3. Candidates must have a cumulative scholastic average of at least 95% and and 1s in responsibility in all subjects. Candidates will then be evaluated on the basis of service, leadership and character.
4. Selection for membership is done by a faculty council.
5. Once selected, members have the responsibility to continue to demonstrate the above qualities necessary for membership. Failure to do so may result in the student being placed on probation or asked to leave the society.