Budesonide–salbutamol combination therapy provides rapid symptom relief and sustained anti-inflammatory control in asthma. Dry powder inhalers (DPIs) offer improved formulation stability, but the combination is currently available only as pMDI formulations. This study aimed to develop and evaluate a DPI formulation capable of efficiently delivering budesonide and salbutamol to the deep lung. Salbutamol and budesonide microparticles were prepared by jet milling. Carriers with particle sizes of 4–11, 40–70, and 180–250 μm were screened to select a suitable carrier. Formulations were prepared by blending the selected carrier with drug particles produced by single jet milling, co-jet milling, or compression followed by co-jet milling. Particle size, flowability, morphology, and aerosol performance were evaluated by PSD, tapped density, SEM, and NGI. The jet-milled particles showed a Dv50 below five micrometers, indicating suitability for inhalation. Compression followed by co-jet milling improved powder flowability. The formulation with the smallest carrier particles showed the highest fine particle fraction (FPF) of about 53.5%, whereas formulations with medium and large carriers showed FPF of about 20.6% and 16.9%, respectively. In this formulation, compression followed by co-jet milling enhanced budesonide FPF to about 54%, while salbutamol reached about 60% FPF. In conclusion, process optimization improved the aerosol performance of the salbutamol–budesonide DPI, suggesting its potential as an alternative to pMDIs.