Negative relationships between mathematics anxiety and achievement appear in many countries globally (Lee, 2009; OECD, 2013), suggesting that mathematics anxiety could be an underconsidered factor in regions with persistently low mathematics achievement. We draw on a national sample of students and their teachers in Belize to examine relations between mathematics anxiety and achievement. The data replicated the negative relationships between students' math anxiety and achievement observed in many higher achieving, higher resourced regions, and importantly also revealed that teachers' mathematics anxiety predicted their students' mathematics attitudes and sometimes achievement. The effects were small overall so the robustness of this relationship is not clear, but they provide novel data toward building a comprehensive theory of mathematics anxiety's relationship to achievement across cultural, gender and age contexts, and offer insight into how addressing mathematics anxiety might improve mathematics teaching and achievement in low resourced countries. [This article was published in "Mind, Brain, and Education" (EJ1277351).]