Copper is an essential micronutrient but can be toxic at elevated levels. Monitoring copper in aqueous systems is critical for characterizing pollution sources and mitigating human health risks. This chapter comprehensively evaluates recent advances in analytical methods for detecting copper, including atomic spectrometry, molecular spectrophotometry, electrochemical sensors, voltammetry, and chromatography. Each technique’s critical detection limits, selectivity, complexity, and advantages are outlined. Atomic absorption spectrometry, inductively coupled plasma-optical emission, and inductively coupled plasma-mass spectrometry provide the most sensitive copper quantification down to parts per trillion levels. Meanwhile, spectroscopic methods using novel reagents offer inexpensive and rapid copper screening. Electrochemical and optical sensors show promise for on-site and continuous monitoring. Chromatographic separation before detection improves selectivity in complex sample matrices. Critical evaluation of these complementary approaches can inform the selection of optimal copper quantification techniques for different environmental, industrial, and biological monitoring applications. Recent advances continue to expand the analytical toolkit for sensitive, selective, and cost-effective copper analysis across diverse aqueous systems.