The looking-while-listening (LWL) paradigm is frequently used to measure toddlers’ lexical processing efficiency (LPE). Children's LPE is associated with vocabulary size, yet other linguistic, cognitive, or social skills contributing to LPE are not well understood. It also remains unclear whether LPE measures from two types of LWL trials (target-initial versus distractor-initial trials) are differentially associated with the abovementioned potential correlates of LPE. We tested 18- to 24-month-olds and found that children's word learning on a fast-mapping task was associated with LPE measures from all trials and distractor-initial trials but not target-initial trials. Children's vocabulary and pragmatic skills were both associated with their fast-mapping performance. Executive functions and pragmatic skills were associated with LPE measures from distractor-initial but not target-initial trials. Hence, LPE as measured by the LWL paradigm may reflect a constellation of skills important to language development. Methodological implications for future studies using the LWL paradigm are discussed.