Learning outcome (LO) literacy is conceptualized as a necessary skill for planning teaching and learning activities effectively. The skill has two main components: understanding and interpreting learning outcomes. The current study aimed to identify learning outcome literacy of elementary mathematics teachers with regard to this conceptualization. It is a case study based on the qualitative design. Participants were 5 mathematics teachers working at different elementary (5th - 8th grade) schools in Turkey. Observations and semi-structured interviews were used for data collection based on 10 learning outcomes selected from algebra and number learning domains in local mathematics curriculum. Content analysis method was used for data analysis. According to the findings, LO literacy can be regarded as a basic teacher competence and it requires the teacher to use the knowledge and skills he/she has. The results showed that participant teachers' LO literacy was insufficient. Considering the interrelation among its components, LO literacy should be developed with all the sub-components for effective teaching of LOs.