This study investigated environmental and personal factors that explain functional skills and caregiver assistance in young infants/toddlers. Methods: A cross-sectional study was conducted involving seventy-four children with typical development between 6 and 18 months of age. Functioning skills were evaluated using the Pediatric Evaluation of Disability Inventory, and the home environment was evaluated using the Affordances in the Home Environment for Motor Development-Infant Scale. Statistical analyses were performed by regression models. Results: Child's age explained 45% of self-care (β = 0.68); child's age (β = 0.72), attending daycare (β = 0.33) explained 71% of mobility, and child's age (β = 0.80) and breastfeeding duration (β = 0.17) explained 69% of social function. With regards to caregiver assistance, child's age (β = 0.46), attending daycare (β = 0.20) and number of siblings (β = -0.22) explained 31% of self-care; child's age (β = 0.62) and attending daycare (β = 0.34) explained 56% of mobility; and child's age (β = 1.91) and total AHEMD-IS score (environment) (β = 2.63) explained 30% of social function. Conclusion: Daycare, breastfeeding duration, number of siblings, stimulation at home, and age explained functional skills and caregiver assistance to toddlers/infants.