This study surveyed 19 chemistry teachers' stoichiometry pedagogical content knowledge (SPCK) in Ijebu Ode local government area of Ogun state, Nigeria using Malcolm's Physical Science Teachers' SPCK test. The qualitative data were transformed to scores, which revealed the level of chemistry teachers' knowledge of students' prior knowledge, curriculum saliency, what makes stoichiometry easy or difficult to understand representations and conceptual teaching strategies. In addition, the study determined how the level of teachers' SPCK is related to students' stoichiometry achievement. The results showed that 89% of the chemistry teachers provided novice or basic responses for all the five components of SPCK. The group mean of teachers' responses for each of the SPCK components revealed that the teachers had the highest knowledge level for the component of what makes stoichiometry easy or difficult to understand. The group means for the other four SPCK components are below the basic level; specifically, the knowledge of representations and analogies used in stoichiometry teaching and of conceptual teaching strategies were at a very low SPCK level. Out of the 19 teachers, six are classified as novices, eleven are basic and two are developing experts. The results also showed that the teachers' SPCK level is associated with students' achievement in stoichiometry, in that, the students of the developing expert teachers had a significantly higher achievement than their peers taught by the novice and basic level SPCK teachers. Therefore, it is recommended that in-service and pre-service chemistry teachers are exposed to training that will improve their SPCK specifically regarding students' prior knowledge, curriculum saliency, representations and conceptual teaching strategies.