Research Findings: The purpose of this study was to examine the potential contribution of teacher-child interactions to residualized Inhibitory Control (IC) gains over approximately a six-month period for preschoolers from predominantly low-income households. The study also explored whether the association between quality of teacher-child interactions and IC gains depends on children's IC skills upon classroom entry and their household income-to-needs ratio. The study included 169 preschoolers from 51 classrooms in a Head Start program run by an agency in a large city in Oklahoma. Children's IC skills were assessed in fall (time 1) and spring (time 2), and teacher-child interaction quality was observed at fall (i.e., September through November). Results from Hierarchical Linear Modeling (HLM) did not show significant effects of high-quality teacher-child interactions on residualized IC gains over six months. However, results showed that children who initially presented poor IC skills displayed higher gains in their IC skills at spring when they were in classrooms practicing high-quality teacher-child interactions, as defined by emotional support and classroom organization. Practice or Policy: Emotionally supportive and well-organized classrooms in Head Start programs may benefit early IC development, especially for children presenting poor IC skills at classroom entry.