Precise control of the compositional profile in ternary semiconductors, with the resulting spatial variation of band structure, allows electronic and/or optical properties to be tailored for specific applications. An algorithm is presented, and its implementation described, for the growth of very narrow graded compositional GaAs/AlGaAs heterostructure wells and barriers by conventional solid‐source molecular beam epitaxy. The Al source furnace temperature is controlled continuously to obtain linear analog compositional grading. Physical confirmation of the precision of the profiles has been obtained by a range of techniques including secondary ion mass spectrometry, secondary neutral mass spectroscopy, and compositional analysis from thickness fringes‐transmission electron microscopy. The results show excellent linearity and symmetry in structures with compositional changes between 0% and 30% Al over 10‐nm graded regions.