Airway multiciliated cells (MCs) maintain respiratory health by clearing mucus and trapped particles through the beating of motile cilia. While it is known that ciliary lengths decrease along the proximal-distal (P-D) axis of the tracheobronchial tree, how this is regulated is unclear. Here, we demonstrate that canonical Notch signaling in MCs plays a critical role in stabilizing ciliary length. Inhibition of Notch signaling in MCs results in ciliary shortening in the trachea, lengthening in the distal airway, and to region-specific alterations in gene expression. We probe how environmental challenges impact MC homeostasis using germ-free and Mycobacterium tuberculosis ( M. tb ) infection models. While germ-free conditions do not perturb ciliary lengths, M. tb infection leads to lengthening of distal airway cilia, correlating with a downregulation of Notch signaling. These findings reveal that ciliary length and the P-D gradient in the airways are actively regulated, with Notch signaling serving as a stabilizing mechanism.