Dental and skeletal endemic fluorosis continue to be a public health problem in severalrnparts of the world including Ethiopia (especially in the Rift Valley Region), whererndrinking water contains fluoride much higher than the WHO permissible limit (1.5rnmg/L). Development of appropriate defluoridation technologies is important inrndeveloping countries like Ethiopia to mitigate the irreversible health impacts of fluoridernin drinking water.rnIn this study, manganese oxide modified aluminium oxide hydroxide (MOAOH) wasrnprepared from manganese (II) chloride and aluminium oxide hydroxide and its fluoridernremoval capability has been investigated. The parameters considered were effect ofrnpercentage of manganese oxide, adsorbent dose, contact time, initial concentration ofrnfluoride, and initial pH of the water. Removal efficiency of the adsorbent variedrnsignificantly with percentage of manganese oxide with an optimum value of about 11%rnof manganese oxide in the adsorbent. The removal efficiency increased with increasingrnadsorbent dosage. It was found that the optimum dose is 4 g/L which corresponds to thernequilibrium adsorption capacity of 4.8 mg F-/g. Adsorption capacity showed anrnincreasing trend with an increase in initial fluoride concentration in the water.rnThe removal of fluoride by MOAOH also varied with the initial pH of the water. The pHrnfor optimum fluoride removal was found to be in the range between 5 and 7. Atrnoptimized conditions removal efficiency exceeding 96% was achieved under thernexperimental conditions used in this study. The adsorption data was analyzed using thernFerundlich, Langmuir, and D-R models. The results showed that the experimental datarncan be well described these models. The minimum adsorption capacity obtained using thernFerundlich isotherm model is 4.48 mg F-/g and the maximum capacity from the Langmuirrnisotherm model is 18.62 mg F-/g. The mean free energy estimated from the D-R model isrn9.71 kJ/mole, suggesting that the adsorption process is primarily chemisorption. Thernkinetic analysis showed that the adsorption is well described by a pseudo-second orderrnreaction model with an average rate constant of 3.4689 x 10-2 g min-1 mg-1. The adsorbedrnfluoride could be easily desorbed by treating with 1.0% NaOH solution. It is concludedrnVIIIrnthat, MOAOH is highly promising adsorbent for removal of excess fluoride fromrndrinking water.