Guerilla Marketing is an advertising strategy that focuses on low-cost marketing tactics mostly adopted by small scale concerns and yields unconventional results. The term Guerilla marketing was inspired by Guerilla warfare which is a form of irregular warfare and relates to the small tactical strategies used by armed civilians. Due to lack of resources, small business houses use different set of marketing strategies and tactics in comparison to big business houses. Guerilla marketing involves unusual approaches such as intercept encounters in public places, street giveaways of products, PR stunts, or any unconventional marketing intended to get maximum results from minimal resources. More innovative approaches to Guerilla marketing now utilize mobile digital technologies to engage the consumer and create a memorable brand experience. So many small firms can select other Medias and work with low marketing budget. This paper will throw light on new approach to the theory and practice of the Guerilla marketing including principles upon which the concept of Guerilla marketing is based with particular reference to the weapons of Guerilla marketing and also highlighting the ethical issues involved in Guerilla marketing.