Three inter-related assumptions regarding best practice in second/foreign language teaching and bilingual/immersion education continue to dominate classroom instruction. These assumptions are that: (a) the target language (TL) should be used exclusively for instructional purposes without recourse to students’ first language (L1); (b) translation between L1 and TL has no place in the language classroom; and (c) within immersion and bilingual programs, the two languages should be kept rigidly separate. Research evidence provides minimal support for these assumptions and they are also inconsistent with the instructional implications of current theory in the areas of cognitive psychology and applied linguistics. Based on current research and theory, a set of bilingual instructional strategies are proposed and concrete examples are provided to illustrate how these strategies can be used together with monolingual strategies in a balanced and complementary way.