Ecological systems theory assumes that child development is the consequence of ongoing reciprocal and spiraling interactions between the child and his/her microsystem (immediate home, school, and community environments). The increasing presence of digital technologies in children's immediate environments suggests the need for the proposed theoretical "techno-microsystem". The ecological techno-microsystem situates the developing child in the context of Internet use in home, school, and community environments. Preliminary validation of the ecological techno-microsystem requires description of children's uses of the Internet across three environments and comprehensive measures of child development. Ninety-one children (37 males and 54 females; mean age 10.7 years) completed rating scales of their Internet use. Additionally, parents and teachers completed rating scales of child social, emotional, physical, and cognitive development. Significant correlations between specific uses of the Internet in specific contexts and specific measures of child development support the theoretical utility of the ecological techno-microsystem. The developmental consequences of Internet use varied as a function of elements of the microsystem (e.g., home and school characteristics) and elements of the technology (e.g., instant messaging versus email). (Contains 2 figures and 5 tables.)