Teaching styles were investigated in 28 middle-class sibling dyads (older sibling M age = 8.2 yrs; younger sibling M age = 5.11 yrs) using two sets of block design tasks (five easy; five hard). Older siblings employed a greater number of strategies (i.e. physical demonstrations, scaffolding, corrective feedback) in the hard than in the easy tasks, thus demonstrating the ability to adjust teaching strategies according to task difficulty. Teachers also employed more frequent strategies when learners were younger indicating that they may be sensitive to developmental differences. In the hard tasks, learners responded positively to teacher guidance, but were also more likely to reject the teacher's help, perhaps demonstrating responsibility for their own learning. Findings are discussed in light of current social-cognitive approaches highlighting the important roles of both teacher and learner during episodes of sibling teaching in middle childhood. (Contains 4 tables.)