This is a corpus-based study on adjective use in eighty written compositions by Swedish learners of English from Grade 7 and Grade 9 in junior high school, and from Year 1 and Year 3 in senior high school. The aims of the study are to conduct an analysis of the use of attributive adjectives in noun phrases, and to investigate how attributive adjective use contributes to the syntactic complexity of noun phrases. This study proposes a hypothesis of the complexity of noun phrases in relation to different types of attributive adjectives, that is to say, an assumption that more complex types of attributive adjectives contain more compact information that requires more effort to learn and use.  The investigation shows that Swedish learners of English in junior and senior high school use an overwhelming number of noun phrases without premodifiers. The findings confirm that less proficient students use more adjectives as premodifiers in noun phrases than nouns as premodifiers. The results of the examination also reveal that students from the four school levels investigated use the most common attributive adjectives frequently, which accouts for more than half of the attributive adjectives used. However, a positive trend is that the use of more complex types of adjectives, such as derivational and participial adjectives, steadily increases in number when students advance in school level.  The comparision of the most common attributive adjectives in proportion to other adjectives used in the data from each grade shows that more proficient students use a richer variety of adjectives than less proficient students. Some pedagogical implications in this connection are the need to raise Swedish students’ awareness of different types of adjectives in language teaching and learning. Other pedagogical suggestions are the need to develop students’ skills in elaborating ideas and consolidating syntactic structures in their writing.       Keywords: syntactic development, noun premodification, attributive adjective, Swedish learners of English