This paper presents the e®ect of robotics assisted language learning (RALL) on the vocabulary learning and retention of Iranian English as foreign language (EFL) junior high school students in Tehran, Iran. After taking a vocabulary pre-test, 46 beginner level female students at the age of 12, studying in their¯rst year of junior-high participated in two groups of RALL (30 students) and non-RALL (16 students) in this study. The textbook used was the English book (Prospect-1) devised by the Iranian Ministry of Education for 7th graders, and the vocabulary taught and tested (pre-test and post-test) were taken from this book. Moreover, the treatment given by a teacher accompanied by a humanoid robot assistant in the RALL group took about ve weeks in which half of the book was covered, and the non-RALL group was taught in a traditional method. Finally, the teacher administered the post-test and delayed post-test whose results of repeated measures ANOVA and Two Ways ANOVA indicated that there was a signi¯cant di®erence regarding participants' vocabulary gain and retention in RALL group comparing to non-RALL group. In addition, the teacher reported the students' positive reaction to RALL in learning vocabulary. Overall, the results revealed that RALL has been very in-°u ential in creating an e±cient and pleasurable English learning environment. This study has some implications for technology-based education, language teaching, and social robotics¯elds.