Phosphorylation is one of the most important and ubiquitous modifications in eukaryotic cells. This covalent modification is a major signaling pathway in living beings. A vast array of cellular events, such as proliferation, differentiation, metabolism, signal transduction, and adaptation to environmental stress, and the function of many proteins, hormones, neurotransmitters, and enzymes, are triggered by phosphorylation. For understanding highly interconnected regulatory network, it is essential to identify and quantify phosphoproteins in biological specimens. Currently, this task is accomplished by mass spectrometry-driven phosphoproteomics. This article outlines recent developments in the analysis of phosphoproteins, specifically, the enrichment, detection, identification, and quantification of phosphopeptides/phosphoproteins.