Horizontal collaboration is the pooling of logistics activities and consolidation of supply chains between two or more manufacturers for achieving mutual benefit. The concept of establishing horizontal relationships between supply chain partners has been first introduced by the European Union in 2001. Often, horizontal co-operation can lead to substantial economic benefits where it is a means of sharing risk, making cost savings, increasing investments, pooling know-how, in addition to the ecological benefit behind. To evaluate possible research directions in this area, this paper provides a review of quantitative models develped in literature for successfully establshing horizontal relationships between competing/non-competing partners.The paper also presents a solution framework for integrating green concepts along with the collaboration problem.