Very-preterm (VPT), moderately-preterm (MPT), and full-term (FT) infants' emotion-regulation behaviors were assessed via the Still-Face procedure at a corrected age of four months. As a developmental task during the first year of life, emotion regulation is important for social and cognitive development. Although substantial evidence indicates that VPT infants exhibit emotion-regulation difficulties, little is known about MPT infants' emotion regulation capabilities, this group also possibly being at risk. The participants included 135 parent-infant dyads: 46 VPT (gestational age 24-32 weeks), 51 MPT (gestational age 32-34 weeks), and 38 FT (gestational age 37-41 weeks). The infants' affect, gaze-aversion, and self-comforting behaviors were coded. Preterm infants responded to parental still face in similar fashion to FT infants, displaying robust still-face and recovery effects. The preterm infants exhibited less developed emotion-regulation behaviors, however, manifested in less positive affect and more gaze aversion in the face-to-face and reunion episodes compared to FT infants. With respect to self-comforting behaviors, each group displayed a significantly different pattern of behaviors throughout the procedure, suggesting better emotion regulation skills among MPT infants compared to the VPT infants. The findings on gaze aversion and self-comforting behaviors could have implications for strategies to incorporate into intervention programs supporting development of emotion regulation skills.