The precipitation of mixed metal-aluminum-layered double hydroxides (Me(II)-Al(III)-LDH)) may be an important control of the solubility of Mn(II), Fe(II), Ni(II), Zn(II), and Co(II) in soils, but assessment of this process is hindered by a lack of thermodynamic data. Here, we determined the solubility products (Ksp) of the Me(II)-Al(III)-LDHs formed by these metals based on long-term Me(II)-γAl 2 O 3 sorption studies complemented with X-ray absorption spectroscopy (XAS) measurements. The LDH phases had the chemical formula Me(II) 2/3 Al 1/3 (OH) 2 Cl 1/3. Solubility products were derived as Ksp = (Me 2+) aq 2/3 (Al 3+) aq 1/3 (OH −) aq 2 (Cl −) aq 1/3 , where brackets represent aqueous activity values determined from the equilibrium solution chemistry of the sorption samples. The Ksps are metal-dependent, with values increasing by two orders of magnitude in the order Ni(II) < Zn(II) < Co(II) < Fe(II) < Mn(II). Comparison to the solubility of β-Me(OH) 2 suggests considerable thermodynamic preference of Me(II)-Al(III)-LDH over β-Me(OH) 2 in soil environments and reveals a linear relation between the log-transformed Ksp values of Me(II)-Al(III)-LDH and β-Me(OH) 2. Solubility plots suggest that Ni(II)-, Zn(II)-, and Co(II)-Al(III)-LDH may form in metal-polluted soils. Fe(II)-Al(III)-LDH may occur in riparian soils undergoing reduction, but precipitation of Mn(II)-Al(III)-LDH appears unlikely as it requires [Mn 2+ ] aq much higher than commonly encountered in reducing soils. Additional thermodynamic and field studies are needed to further assess the importance of Me(II)-Al(III)-LDHs in soils and related geochemical systems.