Klebsiella pneumoniae is a WHO priority pathogen associated with high mortality and increasing multi-drug antimicrobial resistance. Despite extensive genome sequencing over the past decade, functional annotation of the K. pneumoniae genome remains limited. To address this gap, we conducted a chemical genomics screen using an ordered transposon mutant library of 4,346 single-gene mutants to systematically profile fitness across 300 diverse chemical and environmental stress conditions. This approach provides genome-wide insight into gene function and enables the identification of conditionally essential and stress-responsive genes. By clustering phenotypic signatures across conditions, we define co-functional gene modules and infer potential functions for uncharacterised and hypothetical genes based on shared phenotypic patterns. This work delivers a comprehensive resource linking genotype to phenotype in K. pneumoniae, advancing functional genome annotation and providing a reproducible, accessible dataset for the research community to explore stress adaptation and antimicrobial resistance in this pathogen.