Proactive interference (PI) is widely understood to be a major source of forgetting in both long-term and working memory. Research has shown that the ability to regulate PI plays a critical role in working memory performance as well as in tasks that rely heavily on working memory, such as mathematical reasoning. Despite extensive research in adults, far less is known about how the ability to resolve PI develops early in life. Recent work from our lab has demonstrated that toddlers are highly susceptible to PI. The present study builds on this work by using eye-tracking to examine PI buildup and resolution in 2.5–3.5-year-olds using a card-matching paradigm known as Delayed Match Retrieval. Toddlers participated in an object-location working memory task using a Tobii TX300 (n = 6) or a Pupil Labs Neon eye-tracker (n = 25). Performance was calculated based on toddlers’ first looks at the match versus non-match cards during the response period. At this interim analysis point, we found that while performance in the first trials of each block was significantly above chance, and in the rest of the trials it was higher in the No_PI than in the PI condition, this difference was not significant. Data collection is still ongoing, but it seems that 3-year-old toddlers have a smaller interference effect than the 2-year-olds in our prior study. This suggests that developmental studies on pre-toddler memory might be underselling babies' capabilities by failing to account for interference.