Tax administrations have been working on how to deal with non-compliance behaviour at minimal cost, while maximizing collections without affecting efficiency operations of entities in an economy. Studies have been done to understand complexity of this behaviour from economic, social norms, ethical and psychological perspectives. Using theory of planned behaviour (TPB), this study embarks on the same journey by investigating the behaviour of consumer as third-party tax enforcer through asking for sales receipts after transaction. From data collected at Dodoma Municipality by questioning 118 respondents, the study unveils that, attitude and subjective norms have a positive effect on intention to ask for sales receipt, while; there was no effect of perceive behaviour control on customer's intention to ask for sales receipt. Most of the customers acknowlege goodness, desirability or importance of asking for sales receipt, which is argued to have implication on effeciency of tax collection exercise. Morover relatives and friends have significant effect of individual behaviour of asking for receipt, thus existance of habit of asking for sales receipt among community members reduces moral and ethical cost of acting as a third-party tax enforcer. Efforts should be directed more toward winning consumers' support rather than using more force on traders, and adoption and use of EFDs should go parallel with other strategies aiming at improving tax collection.