The nutritional value of many native edible plants is not well understood by scientists, leading to their underutilisation. There is a great deal of promise in using weeds as medicinal plants or as sources of pharmaceutical compounds. Developing new drugs has been shown to benefit greatly from the use of medicinal plants that are pertinent to ethnomedicinal knowledge. This study was aimed at a comparative analysis of phytochemical profiling and the bioactive potential of Thuja occidentalis L. (Cupressaceae) and Sonchus asper subsp. asper (L.) Hill (Asteraceae). The results showed that the distilled water extract of Thuja occidentalis has high phenolic (2073±0.017 mg GAE/g) and flavonoid content (1598.8±0.0056 mg QE/g) while the methanolic extract has high tannin (1908±0.0098 mg/g) and alkaloid content (1192±0.095 mg/g). But the methanolic extract of Sonchus asper has high flavonoid (408.8±0.001 mg QE/g), phenolic (259.02±0.006 mg GAE/g), tannin (820.9±0.005 mg/g), and alkaloid content (653.87±0.002 mg/g). The methanolic extracts of both plants showed strong antioxidant potential. In the DPPH assay, the methanolic extract of Thuja occidentalis showed an IC50 of 50.01±0.02 µg/mL, and in Sonchus asper subsp. asper with IC50 value of 50.97±0.017 µg/mL. In the NOSA assay, the methanolic extract of both plants shows strong antioxidant potential with IC50 values of 50.7±0.024 µg/mL and 51.9±0.011 µg/mL, respectively. This study highlighted the presence of phytochemical compounds and antioxidant activity, which is richest in Thuja occidentalis. They provide a great neutraceutical value to this plant.