The purpose of this study was to explore the influence of parent/grandparent-child interactions on child development in families, with a 13 to 36 month old child, residing in an industrial setting on the eastern seaboard of Thailand. As shown in Figure 1, the data emerged into the following themes: a) major parent/grandparent-child activities; b) characteristics of parents’/grandparents’ and children’s behaviors during interactions; and, c) influences of parent/grandparent-child interactions on child development.