Femtosecond transient absorption spectroscopy (FTAS) is an important tool to investigate the physics of halide perovskites having different dimensionality, morphology, and architectures, giving insights into the electronic and excitonic optical transitions. Here, FTAS on monolayer (n = 1) and multilayer (n = 2, 3) quasi‐2D perovskites in the Ruddlesden–Popper phase: DA2MAn‐1PbnI3n+1 (DAMAPI) is presented, with the dodecylammonium (DA = CH3‐(CH2)11‐NH3+) as the spacer and methylammonium (MA = CH3NH3+) as the organic cation for samples with n > 1. The measurements, performed at 77 K and room temperature using several pump energies and excitation densities, allow the observation of different absorption bleaching energies. Those energies are compared with the results of first‐principles theoretical simulations based on density functional theory, the GW method, and the Bethe–Salpeter …