Savannas are mainly characterised by co-existence of woody and herbaceous vegetation. In Namibia, savannas occupy about 64% of the country's land area. They are characterised by the arid to semi-arid climatic conditions and play a vital role in livestock and vegetation production. Most vegetation communities in savannas are influenced by rainfall and species interactions. Change in climatic pattern has shown that a decrease in rainfall can cause more frequent droughts and ultimately decrease the productivity of rangelands and can increase competition among the plants. Savannas present problems for management such as the increase in shrub thickening which can reduce grass production leading to a reduction in the carrying capacity of rangelands. However, there is no consensus yet on the main drivers of shrub encroachment, making it hard to set conservation goals and management recommendations in the savannas. This research intended to assess competitive interactions between woody plants and grasses in the savanna' along a rainfall gradient in Namibia using plant neighbour manipulations. Reciprocal transplant experiments were conducted at three "Options for sustainable geo-biosphere feedback management in savanna systems under regional and global change"(OPTIMASS) sites along a rainfall gradient from November 2016 to April 2017. Seeds of Senegalia mellifera (tree), Anthephora pubescens and Stipagrostis uniplumis (grasses) were collected and sown at their origin site and a neighbour drier site. Germination, survival rates and height growth were measured. Keywords: Anthephora pubescens, clipping, rainfall, Senegalia mellifera, Stipagrostis uniplumis.