The paper considers the writing abilities of Hebrew-speaking grade school and middle school students from mid-high compared with low SES backgrounds, as reflected in stories and compositions they wrote on the topic of friendship. A range of linguistic means of expression were employed as diagnostic of school-age written text construction, focusing on the lexicon and including both devices applicable in different languages (overall text length in words and clauses, syntactic clause density, and lexical diversity and density as reflected in proportions of content words) as well as Hebrew-specific features (verb-pattern morphology and construct-state noun compounds). Analyses showed these features to differentiate across the independent variables of the study: age-schooling level, SES background, and text genre (narrative vs. expository). In terms of genre, expository-type essays usually had denser and more lexically diverse texture than stories. In developmental perspective, lexical usage improved in the texts produced by 13-14 year-olds in comparison with those of 9-10 year-olds. Finally, texts produced by middle-class children attending well-established schools were in general of better lexical quality than those produced by children from disadvantaged backgrounds attending low-achieving schools.