The Western Cape TIMSS 2019 school sample was selected from the 2018 Department of Basic Education (DBE) List of Schools that offered Grade 9 classes. Statistics Canada selected the South African sample and Western Cape provincial sample of 150 schools based on school type (public, independent) as explicit stratification variables and school poverty ranking as the implicit stratification variable. The realised Western Cape sample was 149 schools, 149 principals, 162 science educators, 170 mathematics educators and 5 350 learners. The key research questions framing the analysis of the TIMSS 2019 Western Cape data are: l. What are the mathematics and science achievements and achievement gaps in TIMSS 2019? 2. What are the mathematics and science achievement trends from 2011 to 2019? 3. What influences mathematics and science achievement in Western Cape?