The present study reported the isolation of one sesquiterpenoid (1), two kaurane-type diterpenoids (2, 6), one pimarane-type diterpenoid (7), three lignans (3e5), two aporphine alkaloids (8 and 9) and one flavonoid (10) from the leaves and stems of M. maingayi. All of these compounds, except liriodenine (8), are reported from this plant for the first time. Spathulenol (1), (-)-16-kauren-19-oic acid (2), (+)-epieudesmin (3), eudesmin (4), magnone A (5), didymooblongin (6), (+)-pimaric acid (7), liriodenine (8), oxostephanine (9) and pinocembrin (10) were identified by spectroscopic methods and comparison with literature data. The chemotaxonomic significance of these compounds was discussed in relation to the Annonaceae family, including their occurrence in other genera and their structural characteristics relevant to taxonomic classification.