The syntax of possession exhibits special characteristics in many languages of the world. In particular, inalienable possession nouns appear to contain an internal argument which must be coindexed with the possessor noun. In Romance languages the argument is a dative or accusative clitic. These languages contrast with English-type languages in the following ways: ( 1) the inherent possession noun contains no explicit possessor determiner but a definite article; (2) the clitic is obligatory; and (3) number morphology is under-specified. This study compares the acquisition of inalienable possession syntax in L2 Spanish in order to determine ultimate levels of attainment. Three experimental groups of different proficiency levels and one control group participated in a grammaticality judgment task. Results reveal that the possessor raising structure is not present in the early stages of the acquisition of Spanish, but reaches native or native-like levels at the more advanced stages of acquisition after considerable exposure to the language.