Some embodiments include a capacitor. The capacitor has a first electrode with a lower pillar portion, and with an upper container portion over the lower pillar portion. The lower pillar portion has an outer surface. The upper container portion has an inner surface and an outer surface. Dielectric material lines the inner and outer surfaces of the upper container portion, and lines the outer surface of the lower pillar portion. A second electrode extends along the inner and outer surfaces of the upper container portion, and along the outer surface of the lower pillar portion. The second electrode is spaced from the first electrode by the dielectric material. Some embodiments include assemblies (e.g., memory arrays) which have capacitors. Some embodiments include methods of forming capacitors.