In this study, we assessed possible consequences of bilingualism on executive function among adults. Three groups of adults were tested with a series of tests designed to tap two types of cognitive flexibility: reactive flexibility and spontaneous flexibility (The experimental groups comprised bilinguals equally proficient in Hebrew and English (balanced), Hebrew-dominant bilinguals and English-dominant bilingual participants). The results revealed several significant differences where the balanced bilinguals performed better relative to individuals from the same cultural background. In both types of flexibility tasks, the balanced-bilinguals were found to be superior to the Hebrew-dominant group but not compared to those who mastered English as their primary language. A significant difference between the balanced-bilingual group and the Hebrew-dominant group was found in the task which required spontaneous cognitive flexibility and the one which required reactive cognitive flexibility. The comparison of these unique findings with other findings in the literature and their psycholinguistic implications are discussed.