In present economic scenario, people are exposed to a greater number of commercial messages which cannot be perceived unless they at first instance have grabbed the attention. Customers are getting better at avoiding being influenced by traditional advertising, both by using new technology and simply by mentally blocking them out. Advertisers have used some new advertising media that fell out of audience expectation, they realized that they needed to use innovative, inventive and unconventional tactics, strategies and techniques to keep their customers. Guerilla advertising strategies display creative ideas presented dynamically with unconventional methods at places where advertising would be least expected. The aim is to surprise, irritate, fascinate, and animate the consumer. Guerrilla advertising strategies are characterized as being more creative and eye-catching than traditional methods. Guerrilla advertising strategies are described as being fancy, atypical, unusual, original, provoking, flexible, dynamic, innovative, creative, and humorous. There are three effects distinguish Guerrilla advertising strategies from traditional methods, namely surprise, diffusion and low-cost effect. The aim of this paper is to contribute to in creating a theoretical approach of Guerrilla advertising strategies by addressing the following: what is the origin of guerrilla advertising?, what are the differences between guerrilla advertising strategies and conventional advertising strategies?, what are the philosophy and the principles of guerrilla advertising strategies?, and what are the forms of guerrilla advertising strategies?. This paper assume that the use of Guerrilla advertising strategies makes a far more valuable impression on consumers, and the use of guerrilla advertising portraying the brands as innovative and exciting. The main forms of Guerrilla strategies are analyzed in this paper including Ambient Ad, Ambush Ad, Stealth Marketing, viral marketing, Brand pushers, Celebrity marketing, Video Games Marketing, Guerrilla Mobile, Product placement, Experiential advertising, Affiliate Marketing, Elevator ad, Bathroom Ad, Transit Ad, and Aerial ad