The interaction between floor slabs and the vertical elements in a tall building structure results in a more efficient lateral load resisting system. The study examines the structural behaviour of the floor slab in the following situations: (i) Slab coupling a pair of shear walls in a cross-wall structure under cantilever bending action. (ii) Slab in composite action with a lintel beam connecting a pair of shear walls. (iii) Slab restraining a centre core against torsional warping. (iv) Slab coupling a centre core to a peripheral framed tube in a hull-core structure under cantilever bending action. (v) Slab connecting a row of columns in a flat-plate frame structure under lateral loading. The resistance of the floor slab against the deformation of the vertical elements, and the actions induced in the slab in the various situations are determined by finite element and influence coefficient techniques. The finite element technique idealises the slab-wall structure as an assembly of plate and shell elements and uses an established stiffness analysis to determine the displacements, forces and stress resultants in the slab. The influence coefficient technique approximates the interaction forces between the slab and walls as a system of discrete nodal forces which are determined from the solution of compatibility equations written in terms of plate influence coefficients and prescribed wall displacements. The results of parameter studies are presented in a series of design curves and tables to enable, the effective slab stiffness and slab actions to be readily determined for a wide range of structural configurations. Experimental tests on small-scale shear wall-slab models are carried out to substantiate the general accuracy of the theoretical methods of analysis.