The need for quality teaching is reflected in the poor performance of students in international tests. Teachers' practices and contextual factors could contribute to substandard quality of teaching in South Africa. Several studies indicate that successful learning is largely dependent on the teachers' practices in class. The focus of the present research was to profile the effective teaching practices of 424 secondary-school teachers in the Gauteng Province, South Africa. Teachers were observed by trained observers using a valid and reliable observation instrument measuring six domains of effective teaching practices. Results showed that teachers find it difficult to differentiate in class and to activate learning. Additionally, teachers with more than 15 years of teaching experience scored lower than teachers with less experience, in all six teaching domains. Presumably, experienced teachers may lack motivation and/or insufficient training in implementing interactive and differentiated teaching methods that are needed for effective teaching practices.