Schools have specific expectations to the students according to their socioeconomic status (SES) and academic standing. The school webpage content can reflect these expectations. If students browse their school webpages frequently, school websites may communicate these expectations to the students and unintentionally become an accessory for reproducing social class differences in learning behaviours and academic performance. Nonetheless, few past studies of the function of school websites have examined the use of websites to signal schools' expectations. The present study applied structural topic modelling (STM) to analyse the webpage contents of secondary schools in Singapore and to examine how the SES and academic ability of the students are related to the contents of the school webpages. Webpages of about 90% of secondary schools in Singapore (10089 webpages from 133 schools) have been collected and analyzed. Results show that schools' socioeconomic and academic statuses are related to the relative prevalence of different topics on the school websites. Among the schools that admitted high-ability students, those located in more affluent districts had a greater tendency to mention co-curricular activities that are associated with high society (e.g., art). Moreover, schools in more affluent neighborhoods and those that admitted higher-ability students more frequently showcased their students' achievements in national competitions. In contrast, schools that admitted lower-ability students or those located in less privileged neighborhoods more frequently mentioned outdoor activities and special events, and non-specifically mentioned competitions and prizes. These results indicate that schools admitting students with higher ability and in more affluent neighborhoods have higher expectations on their students. These specific expectations may shape students' behaviors and may infleunce students' academic outcomes. These findings deepen our understanding of how schools signal their expectations according to students' socioeconomic and academic status and provide a policy reference for ameliorating educational inequality.