Post-translational modifications (PTM) involve chemical modifications of amino acid residues within histone and non-histone proteins and are chemically diverse. PTM plays a vital role in regulating the chromatin structure in the nucleus, thus gene regulation. Among the various PTM, reversible acetylation of histone non-histone proteins has fundamental functions in various cellular processes. In all organisms, histone acetylation of lysine residues is connected with transcription activation. Acetyltransferases and deacetylases are well-known enzymes in the acetylation of the histone and non-histone proteins. This chapter will review the latest progress in histone and non-histone reversible acetylation epigenetic alterations and mechanisms and summarize how they affect development, aging, and diseases.