An experimental study on mid-infrared intersubband absorption in InGaAs/GaAsSb multiple quantum wells grown lattice-matched to InP substrates by molecular beam epitaxy is presented. Intersubband absorption in a broad wavelength region (5.8 - 11.6 μm) is observed in multiple quantum well samples with well widths ranging between 4.5 and 12 nm. A conduction band offset at the InGaAs/GaAsSb heterointerface of 360 meV gives an excellent agreement between the theoretically calculated ISB transition energies and the Fourier-transform infrared spectroscopy measurements over the whole range of well widths under investigation. Two kinds of intersubband devices based on the InGaAs/GaAsSb material system are presented: a quantum well infrared photodetector operating at a wavelength of 5.6μm and an aluminum-free quantum cascade laser. The presented quantum cascade laser emits at a wavelength of 11.3 μm, with a threshold current density of 1.7 kA/cm2 at 78 K.