This paper explores the feasibility of an automated, online form of L2 strategy instruction (SI) as an alternative to conventional, classroom-based forms that rely primarily on teachers. Feasibility was evaluated by studying the effectiveness, both actual and perceived, of a five-week, online SI course designed to teach web-based dictionary skills integrated with knowledge of lexical patterns (involving grammatical collocation, complementation, and transitivity). Sixty-four learners in a US university ESL composition course were matched for vocabulary size and then randomly assigned to treatment and comparison groups in a learning management system. The SI treatment comprised multimedia presentations and a variety of practice activities with immediate, specific feedback, while the comparison condition involved recurrent use of dictionaries for referencing vocabulary usage features but no instruction. Performance data showed significant gains among the SI group in contrast to the comparison group, as well as a clear need for such training, while perception data indicated that participants felt the instruction was effective and relevant. The findings point to the as yet untapped potential of this form of instruction to address long-standing cost-benefit concerns about SI, as well as to help learners make more strategic use of CALL resources.