Statistics Canada selected the South African sample and Gauteng provincial sample of 150 schools from the 2018 Department of Basic Education’s (DBE) List of schools that offered Grade 9 classes (648 Public and 348 Independent schools). Public schools accommodate 88% of the province’s learners, and independent schools 12%. The sampling was based on school type (public, independent) as the explicit stratification variables and school poverty ranking as the implicit stratification variable. The realized Gauteng sample was 150 schools, 150 school principals, 151 mathematics and science teachers and 5 633 learners. The key research questions framing the analysis of the TIMSS 2019 Gauteng data are: 1. What are the mathematics and science achievements and achievement gaps in TIMSS 2019? 2. What are the mathematics and science trend achievements from 2011 to 2019? 3. What influences mathematics and science achievement in the Gauteng province?