This study investigated the extent to which teachers' questioning techniques and the way teachers handled students' responses facilitated students' learning and promoted their thinking skills. The study focused on three secondary schools in Dar es Salaam. The data collection process involved classroom observations during chemistry lessons and interviews of 10 chemistry teachers. The findings showed that 80% of the observed teachers had a moderate ability in using questioning techniques to measure students' understanding. The interesting observation in all schools was that teachers interacted frequently with active students and bothered less to involve the least active ones. Moreover, above 80% of all teachers had problems of promoting students' thinking by maintaining a balance between the open- ended and close-ended questions or between convergent and divergent questions. Also, the teachers indicated severe weaknesses in guiding classroom discussions through effective questioning as their abilities in probing were low. Thus, in-service program for these teachers may improve their classroom questioning behaviour. (Contains 4 tables.)