Abstract: Microfluidic methods for barcoding nucleic acid target molecules to be analyzed, e.g., via nucleic acid sequencing techniques, are provided. Also provided are microfluidic, droplet-based methods of preparing nucleic acid barcodes for use in various barcoding applications. The methods described herein facilitate high-throughput sequencing of nucleic acid target molecules as well as single cell and single virus genomic, transcriptomic, and/or proteomic analysis/profiling. Systems and devices for practicing the subject methods are also provided.