Nutritional exposures during pregnancy and the first two years of a child’s life influence growth and risk for obesity. Upstream interventions that involve policy, systems, and/or environmental approaches may support equitable nutrition and healthy growth early in life. Yet little is known about application of these interventions in clinical settings. This scoping review characterized the breadth, generalizability, and methodological rigor of nutrition-focused, upstream interventions for obesity prevention during the first 1,000 days in clinical settings. Eight databases were searched in November 2022 for policy, systems, and/or environmental approaches conducted during the first 1,000 days. Of the 73,969 records identified, 185 reports representing 126 studies were included. Studies frequently involved combinations of system (98%), environmental (56%), and/or individual (87%) approaches in prenatal care (35%), hospital (22%), or primary care (21%) settings. Over half (62%) were conducted with socially disadvantaged families. More studies reported positive effects on feeding practices (71%), child diet (70%), breastfeeding (67%), and maternal diet (62%), compared to child (31%) or maternal (48%) weight and growth outcomes. Results suggest the promise of scaling adoption of policy, systems, and/or environmental approaches that enhance standard clinical care by incorporating nutrition-focused elements to support healthy feeding behaviors and growth.