The microstructure of zinc oxide particles precipitated in the presence of a poly(ethylene oxide-block-methacrylic acid) (P(EO-b-MAA)) and a poly(ethylene oxide-block-styrene sulfonic acid) (P(EO-b-SSH)) diblock copolymer was investigated. The crystals precipitated with the P(EO-b-MAA) copolymer consist of a region with a lower but still relatively high order close to a central grain boundary and regions of very high order further away from the central grain boundary. Selected area diffraction (SAD) found single crystalline particles in the control sample, confirmed the formation of single crystalline domains with slightly different orientations with the P(EO-b-MAA) copolymer, and confirmed the formation of a mosaic texture with the P(EO-b-SSH) copolymer. High-resolution transmission electron microscopy images exhibit little defects in the control sample. More defects are found close to the central grain boundary in the sample precipitated with P(EO-b-MAA). With the P(EO-b-SSH) copolymer, a single crystal core carries a number of lamellae, which are bent with respect to each other. Powder X-ray diffraction confirms the formation of zincite and shows a reduction of the coherence length when the crystals are precipitated in the presence of the polymers.