The present study investigates the role of first language (L1), in our case Cypriot Greek (CG) or Standard Greek (SG), in the second language (L2) acquisition of English present perfect in terms of form and meaning possibilities. With respect to native speakers of CG in particular, the primary goal is to determine whether transfer from the mother-tongue, in which present perfect has only a resultative reading and simple past a resultative, an existential or a definite reading, influences the acquisition of the English present perfect. It is assumed that L2 acquisition involves establishing connections between the semantic properties/overt markers for each reading and the English present perfect. Diagnostic tests proposed by Agouraki (2006) are employed in this study, based on the (in)compatibility of certain types of adverbial markers with the existential reading and the resultative reading, respectively, as well as on the distinct semantic properties of the two readings. Almost 400 participants took part in this research. The results show that there is a certain effect of L1 on the L2 acquisition of English present perfect by CG- and SG-speaking pupils, which is argued to be mainly due to the different patterns of meanings and forms in CG, SG and English.