Viscoelastic drop deformation under electric fields plays a key role in applications such as microfluidics, inkjet printing, and electrohydrodynamic manipulation of complex fluids. In this study, we numerically investigate the deformation dynamics of a neutrally buoyant viscoelastic drop, modeled using Oldroyd–B constitutive relation, suspended in a Newtonian medium under a uniform electric field, using the open-source solver Basilisk. The deformation behavior is governed by the conductivity ratio (${\sigma }_r$), defined as the ratio of the drop to medium electrical conductivity, and the permittivity ratio (${ϵ}_r$), defined as the ratio of the drop to medium permittivity. The deformation further depends on the electric capillary number ($C{a}_E$), which represents the ratio of electric to surface tension forces, and the Deborah number ($De$), which represents the ratio of the polymer relaxation time to the flow timescale. The resulting (${\sigma }_r$, ${ϵ}_r$) phase diagram comprises six regions, three exhibiting stable spheroidal (prolate/oblate) deformation, while in the remaining three, the drop remains spheroidal below a critical $C{a}_E$ and transitions to multi-lobed shapes, conical-tip formations, or oblate breakup above this threshold. We systematically examine these regions over a range of $C{a}_E$ and $De$ to elucidate the role of viscoelasticity in governing the deformation dynamics. Elasticity is found to suppress deformation in prolate regions, leading to reduced deformation with increasing $De$ due to the buildup of polymeric stresses near the poles. In contrast, elasticity enhances the oblate deformation as polymeric stresses accumulate near the drop center and extend along the symmetry axis with increasing $De$.