Background/Objectives: Television viewing has been linked with increased weight and obesity, likely through decreased physical activity associated with sitting and viewing television, as well as increased intake of food, likely through reduced awareness of eating and intake behaviours. This review sought to determine the effects of television viewing on energy intake relative to the absence of television. Methods: We adhered to the PRISMA guidelines and pre-registered this review in PROSPERO (CRD42023493092). The PICOS strategy included children, adolescents and adults of all ages (P), exposed to television viewing only during meals (I) compared to no television and no other distractors (C), with the outcome as energy intake or consumption (O) for both within-subject and between-subject randomised controlled trial (RCT) designs (S). Results: Robust-variance meta-analyses of k = 57 effect sizes from 23 studies showed no overall effect, noting high heterogeneity. When analyses were limited to television alone with k = 29 effect sizes from 23 studies, we revealed a small significant effect of television viewing on intake (g = 0.13, 95% CI [0.03–0.24]) compared to no television. Moderation analysis showed that television viewing strongly increased intake at the next meal (g = 0.30, 95% CI [0.03–0.57]) but not immediate intake (g = 0.10, 95% CI [−0.01–0.21]). Conclusions: This review showed that television viewing increases food intake, especially at the next meal. This effect was evident across both children and adults. This review highlights how television viewing impacts intake and offers potential avenues for intervention based on our findings.