It has become widely accepted that teachers are important in facilitating student learning. Hundreds of empirical studies have tried to explain differences in student performance by evaluating the impact of particular teacher characteristics. Yet, this topic has not been the subject of a systematic review for more than 10 years, even though most of the empirical evidence has emerged over the past decade. This study provides an up‐to‐date review, drawing on empirical findings from several countries and distinguishing between acquired and sociodemographic teacher characteristics. This review confirms the existing consensus that subject‐related degrees and knowledge, and not general teacher certifications, are positively related to student performance and particularly so for Master's degrees in math and science. A new insight is that recent findings point out that teacher experience continues to contribute to student test scores throughout a teacher's career, instead of merely the first few years. An important future research avenue would be to examine which mechanisms can explain these teacher characteristic effects.