Let G = (V (G), E(G)) be a connected graph. A nonempty set S ⊆ V (G) is a total outer- connected dominating set of G if S = V (G) or S is a total dominating set of G and the subgraph (V (G) \ S) induced by V (G) \ S is connected. The cardinality of the smallest total outer-connected dominating set of G is called total outer-connected domination number of G, denoted by γ ̃_tc (G). A total outer-connected domination number of G with cardinality equal to γ ̃_tc (G) is called γ ̃_tc-set of G. This paper presents the characterization of total outer-connected dominating sets in a connected nontrivial graph. It also investigates the total outer-connected dominating sets in the join of two graphs and determine the corresponding value of the total outer-connected domination number.