The traditional fishing with Albezia gummifera could not be environmentally friendly to the aquatic ecosystem. This study investigated the sub-lethal effects of crude back extracts of A. gummifera on histology of gills, liver, kidney and gonads of Clarias gariepinus juveniles. Fish juveniles were exposed to sub-lethal concentrations (1.00, 2.00 and 3.00 g/L) obtained by using 1/10th, 1/15th and 1/20th of 2.5g/L LC50 value of A. gummifera for 56 days with untreated control (0.00g/L). The routine Paraffin wax method and hematoxylin eosin staining techniques of tissue processing were adopted for the examination of the organ histology of the exposed fish. The organ histomorphology in C. gariepinus juveniles from the control 0.00g/L tanks showed normal morphology. Histopathological lessions increase with an increase in the concentration of the plant extract. Alterations in gills are slight atrophy in midline cartilage and primary lamellae as well as complete loss of secondary lamellae. The liver exhibited atrophy, inflammation, and slightly thickened cellular demarcations and the nuclei are severely shrunken. The kidney indicated atrophy as evidenced by the increase in interstitial spaces and necrosis as seen by the loss of cellular materials. Testes showed severe atrophy, massive tissue degeneration, and massive loss of spermatozoa and the seminiferous tubules appear empty. Ovarian damages are atrophy and shrunken perifollicular cells, the previtellogenic oocyte and vitelline envelope are greatly reduced in size and there is loss of vitellogenic oocyte. In conclusion, sublethal concentrations of crude back extract of A. gummifera induced histological alterations in some vital organs and reproductive organs of C. gariepinus juveniles therefore it should be used with caution during fishing.