Background: Strategy-focused writing instruction trains students both to set explicit product goals and to adopt specific procedural strategies, particularly for planning text. A number of studies have demonstrated that strategy-focused writing instruction is effective in developing writing performance. Aim: This study aimed to determine whether teaching process strategies provides additional benefit over teaching students to set product goals. Sample: Ninety-four typically developing Spanish sixth-grade (upper primary) students. Method: Students received 10 hr of instruction in one of three conditions: Strategy-focused training in setting product goals and in writing procedures (planning and revision; Product-and-Process), strategy-focused training in setting product goals (Product-Only), and product-focused instruction (Control). Students' writing performance was assessed before, during, and after intervention with process measures based on probed self-report and holistic and text-analytic measures of text quality. Results: Training that included process instruction was successful in changing students' writing processes, with no equivalent process changes in the Product-Only or Control conditions. Both Process-and-Product and Product-Only conditions resulted in substantial improvements in the quality of students' texts relative to controls, but with no evidence of benefits of process instruction over those provided by the Product-Only condition. Teaching process substantially increased time-on-task. Conclusions: Our findings confirm the value of strategy-focused writing instruction, but question the value of training specific process strategies.