The ethyl acetate fraction of Bougainvillea 'Scarlett O'Hara' cultivated in Egypt did not receive enough attention in phytochemical and biological studies. This inspired the authors to investigate the phytochemicals of this fraction for the first time using UPLC-ESI-MS/MS in negative and positive ionization modes to understand the distribution of the major secondary metabolites. The analysis revealed the tentative identification of fifty-seven compounds. The detected metabolites belonged to numerous chemical classes including seven organic acids, fourteen phenolic compounds, one betacyanin, seven anthocyanins, ten flavonoids, three saponins, six tannins, four cyclic tetrapyrolic derivatives and five miscellaneous. The LC-ESI-MS methodology in negative ionization mode was the most appropriate to detect the group of saponins (22.17%), flavonoids (14.27%), free organic (12.35%) and phenolic acid derivatives (14%). It can be seen that the highest ionization rate produced for cyclic tetrapyrolic derivatives (56.41%), anthocyanins (18.8%) and tannins (3.2%) in the positive mode chromatogram.