Aedes aegypti is a mosquito species responsible for considerable global mortality and morbidity, through its role as the vector of many arboviruses, including dengue, Zika and Chikungunya virus. For Ae. aegypti and many other mosquito species, the predominant method of vector control is insecticide use. However, their widespread deployment over the last hundred years has led to the inevitable rise of insecticide resistance. Insecticide resistance in Ae. aegypti has been documented in most countries where the species is endemic. This thesis uses genomic approaches to develop tools that provide insight into the diversity of global Ae. aegypti populations and analyse the genes and mutations associated with insecticide resistance. Detection of resistance has historically relied on time-consuming phenotypic bioassays, however, in recent years focus has shifted to molecular assays to objectively identify resistance markers. Genomic approaches can inform on mutations that confer resistance and the population structure and diversity within the species. I have developed a barcoded multi-target amplicon sequencing panel for high throughput detection of single nucleotide polymorphisms (SNPs) in gene regions linked to insecticide resistance in Ae. aegypti (voltage-gated sodium channel (vgsc), resistance to dieldrin (rdl), acetylcholinesterase-1 (ace-1) and later glutathione-S transferase 2 (GSTe2)). This panel can be used for the surveillance of resistance alongside traditional bioassays. This methodology has been implemented on multiple populations, including Ae. aegypti sourced from Cabo Verde and Puerto Rico and has identified previously reported insecticide resistance SNPs as well as additional putatively novel missense SNPs. Utilising whole genome sequencing data can provide further insights into ongoing selective pressures due to insecticide use and uncover population dynamics. I carried out a study employing comparative genomics to assess differences in the main insecticide resistance associated genes (vgsc, rdl, ace-1 and GSTe2) in 729 Ae. aegypti sequences from 15 countries. This led to the identification of 747 missense mutations, of which five have previously been associated with insecticide resistance. Combining this genomic data with available phenotype data indicates these profiles are variable, and further investigation into the functional link between mutations and phenotype is required. Creating this large catalogue of genotype data along with the geographic distribution will help to identify resistance drivers and aid monitoring and surveillance efforts in Ae. aegypti. Analysis was expanded by whole genome sequencing 33 Ae. aegypti from a Puerto Rican population and comparing the results to 215 other publicly available global sequences. This analysis highlighted similarities and differences between the Puerto Rican and other global populations with respect to population structure, and genome-wide nucleotide diversity and selection markers. I identified over 281,000 missense SNPs across all populations including four insecticide resistance SNPs (vgsc V410L, V1016I, F1534C; rdl A301S). Signals of selection were found in genes associated with insecticide resistance, including gamma-aminobutyric acid receptor subunit alpha, glutathione S-transferases and cytochrome P450s. This thesis underscores the focal role of genomic techniques and their analysis in enhancing our understanding of insecticide resistance, which can subsequently aid and inform vector control programmes. The identification of mutations known to be associated with resistance is important for assessing vector profiles, and the reporting of candidate novel putative mutations can launch follow-up validation work, including functional studies. Through the implementation of these techniques, surveillance and control can be improved to disrupt transmission and subsequently alleviate the huge global burden of vector-borne disease.