Purpose: This paper aims to investigate the determinants of organic food buying behaviour in an emerging economy like India, where organic food yet has low market share in spite of its potential. Using the theory of planned behaviour (TPB) as the underlying basis, it attempts to explain the effect of attitude, subjective norms and the perceived behaviour control (PBC) on buying intention towards organic food among respondents in Delhi-National capital region, India. Additionally, it attempts to discriminate functional and constructive attitudes. Design/methodology/approach: A quantitative questionnaire survey approach was used on 306 respondents and multiple linear regression was used to validate the research model. Findings: Attitudes and PBC have a significant positive impact on the intention to purchase organic food. This paper found subjective norms to be weak and barely significant to intention. The results conclude that health motives, past purchase behaviour, knowledge, affordability and trust in organic certification label are the main facilitators in organic food purchase. Primarily, the respondents see buying organic food regularly as being of value and enjoyable to them. A more favourable appearance vs conventional food was negatively related to behavioural intention. Originality/value: This research could aid all stakeholders in the organic food sector, particularly emerging economies like India where the organic market is still nascent. It could be an essential driver to improve customer involvement and thus aid them in the decision-making process to choose organic food over conventional food. It also attempts to establish the usability of TPB in assessing functional attitudes based on constructive attitudes for organic food purchase. © 2020, Emerald Publishing Limited.