Purpose: The authors examined associations between preschoolers’ daily glycemic variability, parents’ report of hypoglycemia fear, and preschoolers’ daily moderate to vigorous physical activity (MVPA) and sedentary behavior (SB) in 25 families of preschoolers with type 1 diabetes. Methods: Parents completed a valid measure of hypoglycemia fear, and their child wore an accelerometer for up to 7 days. Parents provided glucose data from their child’s devices. The authors used multiple regression and multilevel modeling to analyze their data. Results: Preschoolers (mean age 4.2 [1.7] y; 50% boys) engaged in a mean of 154.5 (59.6) and 339.2 (85.1) minutes of MVPA and SB per day, respectively, and parents reported relatively low levels of hypoglycemia worry and avoidance behaviors. Preschoolers’ SB (r = .19, P = .02) and MVPA (r = −.20, P = .01) levels were significantly correlated with parental hypoglycemia worry scores but not with parents’ hypoglycemia behavior scores (P = .15 and P = .92, respectively). While multilevel models did not show an association between MVPA and preschoolers’ glycemic variability, preschoolers who engaged in more daily SB experienced higher glycemic variability (P = .04). Conclusions: Research exploring MVPA, SB, and parental hypoglycemia fear in preschoolers with type 1 diabetes could have important clinical implications because it may reveal modifiable treatment targets that can impact preschoolers’ health and activity patterns.