The platinum group (alternatively, the platinum group metals or platinum metals) is a collective name sometimes used for six metallic elements clustered together in the periodic table. These elements are all transition metals, lying in the d-block (groups 8, 9, and 10, periods 5 and 6 — in Mendeleev's original table, this area was called "Group VIII").

The six platinum group metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum. They have similar physical and chemical properties, and tend to occur together in the same mineral deposits.

Strictly taken, the three elements iron, cobalt and nickel in the same group have similar physical (e.g. high melting points, high density for period 4 of the periodic table) and chemical properties such as catalyst (iron and nickel work as a catalysts in some industrial processes), forming complex ions such as Fe(CN) 6 4- , the ability of nickel to absorb hydrogen (like Pd and Pt). Maybe the reason is that these metals are 'not precious enough' to be cosidered as platinum group metals.