The complex interactions between people of three or more generations, which is the cornerstone of intergenerational solidarity, has recently gained more attention from academic research but still receives little attention from policy makers and practitioners. This is in part because research that links intergenerational solidarity with happiness of seniors is rare. Many have taken the interaction among different generations, particularly within the context of family, for granted. In Thailand, as the nuclear family became the predominant form of family structure, replacing the strongly knitted extended structure, the once strongly knitted extended structure contributing to multi-generational interactions have become less visible, making it more difficult to discern the impact of intergenerational solidarity on the happiness of the elderly. Based on a survey done in Udon Thani Province in northeast Thailand, this study describes the nature and degree of intergenerational solidarity within the context of typical rural families. From examining components of intergenerational solidarity such as family living arrangements and meal sharing, the findings indicate that the elderly who live in an environment of strong intergenerational solidarity are more likely to feel happier than their counterparts without these strong bonds. Setting the context within the larger context of the policy of governmental support for the elderly in Thailand, we recommend that the Thai government adopt formal programs promoting intergenerational solidarity. In addition to providing the current, meager monthly living allowance, the government should consider policies that would further the happiness of the elderly by promoting intergenerational solidarity as Thailand becomes an aging society. [ABSTRACT FROM AUTHOR]