Purpose: Schools are thought to represent a growing marketing opportunity for food advertisers in many countries. Marketing of unhealthy food to children is linked to the increased prevalence of obesity worldwide. This paper aims to explore ways in which schools respond to commercial activity around food marketing. Design/methodology/approach: A census survey in the Republic of Ireland was employed to investigate the extent of commercial activity in post-primary schools in Ireland, with a focus on food marketing. School policies related to commercialism and promoting healthy living to children and respondents' attitudes to these issues were explored. Findings: Food sales are a prevalent form of commercial activity in schools with 81.4 per cent operating shops or canteens that sell snacks, 44.7 per cent drinks vending machines and 28.0 per cent snack vending machines. A total of 38 per cent of schools reported that they accept for-profit sponsorship and the primary reason was inadequate funding for equipment (91.6 per cent), especially sports equipment. The majority (87.3 per cent) agreed with establishing a national voluntary code of practice in relation to industry sponsorship, which is recommended by the Irish National Taskforce on Obesity. Few schools have policies that refer to commercial sponsorship (7.0 per cent), but schools would welcome receiving guidance and support in developing such policies. Practical implications: The extent of commercial activity in schools and the possible effect on children and their families need to be disseminated widely. A mechanism for monitoring the type and volume of commercialism, and food marketing in particular, in schools in Ireland is necessary. Originality/value: These findings provide a baseline to monitor the future direction of commercialism in Irish schools. (Contains 4 tables.)