Assessment of executive function in young children is amongst the most commonly used cognitive assessments; however, there is a paucity of childhood executive function assessment methods which can be used remotely. Here, we present a novel adaptation of two child-friendly variants of the Stroop task (i.e., “Day-Night”; “Happy-Sad”), which were conducted remotely with a small (N=40) sample of 3-to 5-year-old children of mothers with depression, taking part of a larger clinical trial. During the assessment, children’s heart rate at baseline and during each task was measured using wrist-worn heart rate monitors. The tasks showed good feasibility in this sample, as the majority of children (80%) completed both tasks, with wide variability in task performance and completion time observed across children. Correlation analyses showed that older age and slower resting heart rate were related to better performance and faster completion time on each task. Follow-up regression analyses including age, household income, baseline heart rate, and heart rate reactivity as predictors accounted for significant variability in task performance and completion time for the Day-Night and Happy-Sad tasks. In the final models, age was a significant predictor of task performance and completion time across both tasks. Resting heart rate was not a significant predictor of task performance for either task, but was a significant predictor of completion time across tasks; children with slower resting heart rate completed the tasks faster. Despite limitations, our findings support the feasibility of online, remote assessment of executive function in young children with implications for researchers and clinicians during the Covid-19 pandemic and beyond.