The effects of end constraints on the strain field of off-axis carbon/epoxy tensile specimens with a low aspect ratio have been compared experimentally for two kinds of end-tab shape: the conventional rectangular-shaped tab and a new oblique-shaped tab proposed by Sun and Chung. For specimens with the conventional rectangular tabs, a significant difference was observed between the longitudinal and lateral strains measured at the centre and near the end-tab. In contrast, the oblique tabs effectively relaxed the end-constraint effect and almost removed the inhomogeneous state of deformation in the initial linear elastic range. In addition, for the subsequent non-linear response, the oblique tabs markedly reduced the inhomogeneity in the longitudinal and lateral strain fields. This reduction in end-constraint effects for the oblique tabs led to a remarkably improved independence of location for measurement of the Poisson effect and the longitudinal Young's modulus for specimens with a low aspect ratio of four. Errors introduced in the determination of the in-plane shear modulus were also diminished. The Poisson effect and the Young's modulus evaluated at the centre of various off-axis specimens were influenced only slightly by the tab-shape difference.