This study assessed the effect of adjectives and noun premodifiers on L2 noun phrase comprehension and error types among English Language Learners. We also examined the correlation between L2 noun phrase comprehension and L2 reading comprehension, as well as the contribution of L2 noun phrase comprehension to L2 reading comprehension. One hundred and one Hebrew-speaking 11th graders were tested on the English noun phrase comprehension task, indexing cross-language effects (from L1 to L2). The task included sentences in four conditions, each representing a different noun phrase structure at the syntactic subject position: NN, NNN, AdjNN, and AdjNNN. Participants also completed L1 reading comprehension and L2 vocabulary tests that were controlled for in the correlation and regression analyses. Overall, the results indicate that sentences with noun premodifiers and no adjective premodifiers were more challenging and more susceptible to L1 interference. Partial correlation analyses showed that participants' performance on all four conditions of the noun phrase comprehension test was significantly and positively correlated with their L2 reading comprehension. Multiple regression analyses revealed that higher accuracy and low error rates in the NN and AdjNNN conditions made a unique contribution to L2 reading comprehension, when we controlled for L1 reading comprehension and L2 vocabulary. This study confirmed the significant effects L1 has on L2 syntactic knowledge, which relates significantly and contributes to L2 reading comprehension abilities among adolescent students.