Studies show that spatial ability relates to success in STEM careers (Wai et al., 2009) and that this ability is malleable (Uttal et al., 2012). Language has been identified as an influential factor on the development of spatial ability (Pruden et al., 2011), but relevant studies that address this influence have focused on settings other than the classroom, where decisive learning takes place. Our study presents a qualitative analysis on how teachers present map navigation tasks and how their spatial language use affects class performance. Class observation and discourse analysis was used on six middle school classes. Teachers completed the Santa Barbara Navigational Ability test (Hegarty et al. 2002) as a measurement of their confidence in their navigational ability. Results show various relations between teacher’s spatial language use and class task performance. For instance, teachers tended to encourage the use of landmarks when they realised that student groups were struggling with the task. Also, when teachers did not establish clear beginning points for the route, completing the task in the assigned time became more difficult for the children. There are also indications of a relation between navigational confidence and teacher’s use of spatial language.