Using Singapore as an example, we argue that schools need to equip and encourage teachers to adopt authentic assessment in teaching and learning so as to develop the students' higher-order thinking. The importance of teaching and assessing higher-order thinking in Singapore classrooms is encapsulated in the vision of "Thinking Schools" launched by the Ministry of Education in 1997. Underpinning this vision is a shift from conventional assessment to authentic assessment. Unlike conventional paper-and-pencil tests that focus on knowledge reproduction and low-level cognitive processing skills in artificial, contrived contexts, authentic assessment tasks underscore knowledge construction, complex thinking, elaborated communication, collaboration and problem solving in authentic contexts. However, the creation of thinking schools in Singapore remains a constant challenge as many teachers tend to rely on conventional assessment and are often ill-prepared to implement authentic assessment. By presenting the findings from a recent empirical study, we propose that schools build teacher capacity by providing ongoing and sustained professional development on authentic assessment for teachers.