The kinetics and mechanism of the thermal decomposition of perchlorate, nitrate, chloride, bromide, and iodide complexes of lanthanum with the Schiff base 4-N-(4’-antipyrylmethylidene) aminoantipyrine(abbreviated as AA) have been studied by TG and DTG techniques. The kinetic parameters for the major decomposition stages (stages I and II) were calculated using the Coats-Redfern equation. The rate-controlling process obeys Mampel’s model with random nucleation, with one nucleus on each particle. It is observed that there is no regular variation in the values of the kinetic parameters of decomposition of the complexes as with other common physical constants, namely boiling point, melting point, etc.