The main objectives of this study were to qualitatively evaluate the profile of phytochemical constituents present in aqueous extract of Microcos paniculata leaves (LWE), as well as to evaluate its toxicity, larvicidal and antidiabetic activity. Phytochemical constituents of LWE were determined by different qualitative tests such as Molisch’s test, Fehling’s test, alkaloid test, frothing test, FeCl3 test, alkali test, Salkowski’s test and Baljet test. Toxicity, larvicidal and antidiabetic activity of LWE were evaluated through brine shrimp lethality bioassay (BSLB), standard WHO protocol with slight modification and α-amylase inhibitory assay. LWE revealed the presence of carbohydrates, alkaloids, saponins, flavonoids, triterpenoids and glycosides. In BSLB, the extract was found to safe with 17889.19 μg/mL of LC50 value. Moreover, in larvicidal bioassay, LWE displayed LC50 value as 695.2186 PPM. Again, the extract demonstrated significant (P<0.05) α-amylase inhibition with an IC50 value of 3425.89±438.61 μg/mL. The results obtained in the present study point out that LWE can be possible source of larvicidal and antidiabetic agents.