Abstract: A gravity gradiometer capable of obtaining the vertical component T.sub.zz of the gravity gradient tensor out of the two horizontal components T.sub.xx and T.sub.yy based on Laplace equation: T.sub.zz =-(T.sub.xx +T.sub.yy) comprises a single disc, and two pairs of radially-oriented horizontal axis accelerometers oppositely-mounted on such disc along respective X and Y axes, each pair being capable of providing, respectively, T.sub.xx =T.sub.x1 -T.sub.x2 and T.sub.yy =T.sub.y1 -T.sub.y2 where T.sub.x1 and T.sub.x2 are the respective outputs of the X axis accelerometers and T.sub.y1 and T.sub.y2 are the respective outputs of the Y axis accelerometers. The gravity gradiometer is also capable of obtaining all five independent components of the gravity gradient tensor based on the above Laplace equation and tensor symmetry as follows: One of the above pairs of horizontal axis accelerometers further comprises tangentially oriented horizontal accelerometers capable of providing by subtraction the T.sub.