It also appears to be having dramatic effects. Assessments at the end of the year show improvements in pupils' reading ages of up to 2.5 years.
Progress is less dramatic for others, but the impact on social skills and overall confidence is marked.
Eleven years after the scheme began, reading is considered "cool" and the paired reading club is seen by pupils as the one to be in, not just because of the weekly raffles and rewards that attendance bring. Buddying with a senior, along with friendship and fun, also bring rewards.
The scheme has won accolades for involving senior pupils in community and voluntary work, most notably the Philip Lawrence award for outstanding achievement in good citizenship, and the Diana, Princess of Wales, silver award for voluntary endeavour. It is also accredited as a City and Guilds community involvement module.
In its report on the school last year, HMIE said the paired reading club was "a model of excellence" and it features on Learning and Teaching Scotland's literacy and numeracy website.
The scheme was set up by Peter Maiolani, principal teacher of guidance, and Simone Hughes, a teacher in the English department, in response to concerns about the reading levels of some first-year entrants.
Castlehead's scheme is, it believes, unique in the assessment element that is built in.
Teachers in the English department initially identify pupils with reading needs, and the 5-14 information from the primary schools is used as a further check. The learning support department also conducts reading age tests.
The senior pupils, described as buddies or reading partners, are trained in specific techniques to help the younger pupils in their reading. They sign a contract to participate in the initiative.
The scheme is being run by eight senior pupils, who talk enthusiastically about how they see younger pupils' reading improve,often dramatically.
Lauren Madden, one of the S6 management team, says: "For some of the younger pupils, reading is seen as a bit of a chore because they are not good at it or didn't like it, so their reading has deteriorated. But, by coming here, they find a new hope."
Christopher Taylor, an S1 pupil, says he has not missed a single day of the club and is sure his reading is improving.