Intramolecular chemically initiated electron exchange luminescence (CIEEL) was studied in the alkaline phosphatase triggering of the spiroadamantyl-substituted 1,2-dioxetanes AMPPD and CSPD, which are widely employed in modern chemiluminescent bioassays, particularly in clinical immunoassay applications. Experimental data on the pH dependence of the CIEEL efficiency, the CIEEL emitter fluorescence lifetime, the rate of cleavage of the dephosphorylated dioxetane 2a, the turnover number, and the Michaelis constant are reported and kinetically rationalized, Through this detailed kinetic analysis, the pH effects on the various steps of the CIEEL process were elucidated. Although every step of the triggering involves H+ or HO- ions, it was shown that at alkaline pH and steady-state conditions only enzymatic dephosphorylation of AMPPD and CSPD depends on pH in this CIEEL process. The turnover number is affected only at pH below 9, which reflects a switchover of the rate-determining step of the enzyme dephosphorylation to its phosphorylation at increasing pH. The Michaelis constant depends on pH within the entire range used, which is attributed to the pH effect on the concentration of the catalytically active enzyme form. The present model kinetic studies on the important alkaline-phosphatase-triggered CIEEL reaction provide the necessary mechanistic insights to understand pH effects in such enzymatic processes for the rational design of more effective CIEEL systems.