Developmental composition courses serve a sizable and growing number of Generation 1.5 students, or long-term U.S. resident language learners, and it is believed that language challenges may be part of Generation 1.5 writers' difficulty in controlling the academic register. The current study investigates possible similarities and differences between Generation 1.5 students ("n" = 149) and two other student groups: mainstream first language (L1) writers ("n" = 203) and more traditional second language (L2) writers ("n" = 55), thus determining the extent to which language-use variables distinguish Generation 1.5 texts from those of their classmates. Results indicate significant differences between Generation 1.5 and L2 students on holistic writing quality, word errors, word class errors, verb errors, total identified errors, and spoken features of language. Generation 1.5 and L1 texts significantly differed on academic features of language. Implications are presented, suggesting that developmental Generation 1.5 writing may be more similar to L1 writing than has been previously reported.