The classroom-based study reported in the present paper sought to compare the effectiveness of the focus on forms (FonFs) and focus on form (FonF) approach in teaching English third conditional to Polish high school students. It involved three intact classes, randomly designated as FonF (n = 34), FonFs (n = 36), and Control (n = 35) with a pretest in Week 1, eight treatment sessions in Weeks 2-4, an immediate posttest in Week 5, and a delayed posttest in Week 9. FonFs was operationalized as the Presentation, Practice, and Production (PPP) sequence spread over the treatments whereas FonF as input-based (e.g., input-enhancement) and output-based (e.g., focused communication tasks) activities accompanied by corrective feedback. The tests included a paper-and-pencil test as a measure of explicit knowledge and a dictogloss as a measure of implicit knowledge and awareness of form-function mappings. The two experimental groups outperformed the control group on both measures on immediate and delayed posttests. Such findings testify to the value of both approaches, serving as a basis for the recommendation that FonFs and FonF should be combined in classroom practice. (Contains 3 tables and 2 figures.)