Let W={w_1,w_2,……,w_k} be an ordered subset of V(G) ; then the metric representation ofv∈V(G)with respect toW is defined as the k- tuple r(v/W)=d(v,w_1 ),d(v,〖 w〗_2 ),...,d(v,w_k ). The set W is called a resolving set of G if for allu≠vandu,v∈V(G)satisfyr(v/W)≠r(u/W). A resolving setW of G with the minimum cardinality is the metric dimension of G and is denoted by dim⁡(G). Any resolving with cardinality dim⁡(G) is called dim-set of G or basis of G.Let Wbe a minimum resolving set of G. A subset T W is called a forcing subset for W if W is the unique minimum forcing resolving set containing T. A forcing subset for Wof minimum cardinality is a minimum forcing subset of W. The forcing metric dimension of W denoted by f_dim (W) is the cardinality of a minimum forcing subset of W. The forcing metric dimension of G, denoted by f_dim (G), is f_dim (G)=min⁡{f_dim (W)}, where the minimum is taken over all minimum forcing resolving sets Win G. In this article, we determine the forcing metric dimension for join of two graphs