Environmental education has been included in Czech curricula since the 1980s, albeit without clear evidence of education for sustainable development (SD), which addresses complex socio-economic issues using SD indicators (SDIs), such as charts, single numbers, tables, maps, and (interactive) images. However, understanding such a comprehensive topic requires developing basic mathematical knowledge and skills. In this study, we aimed to analyse the nature, quality, and availability of teaching materials for SD, primarily using SDIs, which could be applied by Czech teachers. For this purpose, we performed a qualitative and basic quantitative content analysis of several descriptors of documents retrieved from a website for teachers, provided by the National Pedagogical Institute of the Czech Republic. A full-text search identified 1376 records, which were analyzed for SD pillars and SDIs. Our results showed that most records (95%) do not contain SDIs in teaching materials. Only 59 records mentioned (128) SDIs, mostly covering the environmental pillar, 26 of which contain a single SDI. The most frequent issues were waste production, treatment, savings, water parameters, and energy consumption. Mathematical skills were used in 56 SDIs, primarily for evaluating data sets and quantitative expressions of an amount. Overall, only a small number of SDIs are used in education for SD, economic and social SDIs are in the minority, and the STEM potential remains untapped.