Protein misfolding and metal ion dyshomeostasis are believed to underlie numerous neurodegenerative diseases, including Alzheimer's disease (AD). The pathological hallmark of AD is accumulation of misfolded amyloid-beta (A beta) peptides and hyperphosphorylated tau (ptau) proteins in the brain. Since AD etiology remains unclear, several hypotheses have emerged to elucidate its pathological pathways. The amyloid cascade hypothesis, a leading hypothesis for AD development, advocates A beta as the principal culprit. Additionally, evidence suggests that tau may contribute to AD pathology. A beta and tau have also been shown to impact each other's pathology either directly or indirectly. Furthermore, metal ion dyshomeostasis is associated with these misfolded proteins. Metal interactions with A beta and tau/ptau also influences their aggregation properties and neurotoxicity. Herein, we present current understanding on the roles of A beta, tau, and metal ions, placing equal emphasis on each of these proposed features, as well as their inter-relationships in AD pathogenesis.