Abstract: A stackable baby bottle assembly with a nestable cap comprises a bottle base, a ring, a nipple, a cap, and, optionally, a sieve. The bottle base includes a plurality of edge members. A plurality of bottle bases may be stacked for storage. When a plurality of bottle bases are stacked, the edge members form space between the bottle bases, thereby permitting air to flow between the bottle bases. The bottle base and cap may include nesting regions, such that the cap may be inverted and snapped onto place onto the bottom of the bottle base, which may be convenient during feeding. A plurality of caps may be stacked for storage.