Attention is essential for all learning. Increasing research suggests that bilingual children have advanced (relative to monolingual children) development of attentional control. The present study includes 80 bilingual and 80 monolingual child participants from a variety of language and age groups (2.5 to 5 year-olds) to systematically investigate how early learning/exposure to more than one language is related to the developmental shift of attention and its implications in early word learning. Results from the present study support an initial bilingual advantage in the Attention Network Test (ANT; a nonlinguistic tasks measuring attentional shifting), with monolinguals demonstrating comparable performance over time. Furthermore, a significant correlation was found between overall accuracy on ANT trials and MCDI, specifically on the selected lexical category of Adjectives. The current study provides new insights into the early developmental trajectory of attention among monolingual and bilingual children and how attention may be crucial for early word learning.