Machtergreifung (German pronunciation: [ˈmaxtʔɛɐ̯ˌɡʁaɪfʊŋ] ( listen)) is a German word meaning "seizure of power". It is normally used specifically to refer to the Nazi takeover of power in the democratic Weimar Republic on 30 January 1933, the day Hitler was sworn in as Chancellor of Germany, turning it into the Nazi German (Third Reich) dictatorship.

The term Machtübernahme ("takeover of power") is also used for this event. Note that, when used in German, both Machtergreifung and especially Machtübernahme retain their more general meanings and the latter is not particularly related to the Nazis. Machtübernahme means any takeover of power, whether peaceful and legitimate or violent and illegitimate.

The term Machtergreifung was first coined by the Nazis themselves in order to portray their accession to power as an active seizure (an alternative term used was Nationale Erhebung 'national rising'). Since Hitler's appointment as chancellor was more a result of intrigue rather than of an active revolution, the term has been criticized by historians and is sometimes replaced with the term Machtübertragung ("handing-over of power") or, more polemically, Machterschleichung ("sneaking into power").