While emphasis on writing instruction has been a main concern in teaching Spanish to bilingual students in the U. S., it is an area in which very few theoretical advances have been made; in Mexico’s case the situation is even more challenging. Therefore, based on classroom observations, and individual interviews with both teachers and students, and on the collection of class syllabi, this paper seeks to describe the current state of affairs regarding Spanish and English writing instruction for bilingual students in both countries. The main objectives are: 1) the analysis and comparison of the diverse teaching methodologies that high school teachers use to teach Spanish and English writing; 2) the analysis of the effects that the specific observed writing instruction has on students’ perceptions about their own writing in both languages; and 3) the analysis of the perceptions that teachers have about their students’ writing.