The paper reports on a multivariate study that examined the contribution of two independent variables‐cognitive / academic proficiency in Ll and attitudes and motivation toward English as a foreign language‐on success in English as a foreign language of two culturally different learners, one identified as a socio‐culturally disadvantaged group and the other as a “regular” group. A description of the development of the instruments used to measure the variables is provided, the results of which indicated that academic proficiency in L1 played the most important role in predicting success in FLL in school context are reported. Within cognitive/ academic proficiency in L1 it is awareness of language use, register, and ability to correct errors in L2 that emerged as the subvariables that differentiated best among the two groups of students. Implications and conclusions of the results to foreign language learning