Mesoporous alumina and γ-Al2O3–NaAlO2 composites with different morphology were produced by soft chemistry methods using polyethylenimine (PEI), pluronic P123 (P123), and polymer–colloid complex (PCC) derived from them as templates in solution. Sodium aluminate was applied as an additive for production of the mesoporous γ-Al2O3–NaAlO2 composite. The obtained samples were characterized by scanning and transmission electron microscopy, atomic force microscopy, Fourier transform IR spectrometry, X-ray diffraction analysis, and low-temperature N2 adsorption–desorption analysis. The effect of sodium aluminate introduction on the morphological features of the obtained samples was investigated. Mesostructured aluminum oxide obtained using individual templates such as P123 and PEI possesses cylindrical pores, whereas applying PCC resulted in the formation slit-shaped pores. The produced mesoporous aluminum oxide and γ-Al2O3–NaAlO2 composite had a narrow pore size distribution and large surface area. This approach was demonstrated to allow for the control of pore sizes and shapes.