We report the growth of InGaAs and InGaAsP quantum well heterostructures on InP substrates with [011¯] oriented grooves. We have shown that growth of these materials on non‐planar substrates can result in lattice‐mismatched layers on orientations other than (100) which in some cases gives rise to dislocations. In addition, the lateral patterning of quantum wells and quantum wire‐like structures has been demonstrated in this material system. Finally, a quantum well laser, wherein lateral patterning of the well thickness was achieved by growing in a flat‐bottomed groove, was fabricated. Without any additional growth steps these lasers exhibit a single stable spatial mode due to the waveguide formed at the groove.