The objective of this paper is to formulate an acceptable definition of teacher quality based on effective use of time during the teaching process. Assessing teacher quality is hampered by the complexity of intersecting criteria in teaching profession. Quality is often defined broadly and in general concepts isolated from the actual classroom processes. Society, politicians, parents, educators proclaim that the quality of teachers matters, but it is difficult to come to a consensus, which markers of teacher quality can be measured reliably and which of these elements do have crucial impact on teaching. The major goal of this paper is to clarify what efficiency means in the teaching-learning process if time is taken as the main criterion; how knowledge can be defined and how teacher efficiency can be used as an objective marker of quality in teaching profession.