Dutch is written using the Latin alphabet. It has a relatively high proportion of doubled letters, both vowels and consonants. This is due to the formation of compound words and also to the spelling devices for distinguishing the many vowel sounds in the Dutch language. An example of five consecutive doubled letters is the word voorraaddoos (supply box).

The diaeresis (Dutch: trema) is used to mark vowels that are pronounced separately. In the most recent spelling reform, a hyphen has replaced the diaeresis in compound words (i.e., if the vowels originate from separate words, not from prefixes or suffixes), e.g. zeeëend (seaduck) is now spelled zee-eend.

The acute accent occurs mainly on loanwords like café, but can also be used for emphasis or to differentiate between two forms. Its most common use is to differentiate between the indefinite article 'een' (a, an) and the numeral 'één' (one); also 'hé' (hey, also written 'hee').

The grave accent is used to clarify pronunciation ('hè' (what?, what the ...?, tag question 'eh?'), 'bèta') and in loanwords ('caissière' (female cashier), 'après-ski'). In the recent spelling reform, the accent grave was dropped as stress sign on short vowels in favour of the accent aigu (e.g. 'wèl' was changed to 'wél').

Other diacritical marks such as the circumflex only occur on a few words, most of them loanwords from French.

The most important dictionary of the modern Dutch language is the Van Dale groot woordenboek der Nederlandse taal,[7] more commonly referred to as the Dikke van Dale ("dik" is Dutch for "fat" or "thick"). However, it is dwarfed by the 45,000-page "Woordenboek der Nederlandsche Taal", a scholarly endeavour that took 147 years from initial idea to first edition.

The official spelling is set by the Wet schrijfwijze Nederlandsche taal (Law on the writing of the Dutch language; Belgium 1946, Netherlands 1947; based on a 1944 spelling revision; both amended in the 1990s after a 1995 spelling revision). The Woordenlijst Nederlandse taal, more commonly known as "het groene boekje" (i.e. "the green booklet", because of its colour), is usually accepted as an informal explanation of the law. However, the official 2005 spelling revision, which reverted some of the 1995 changes and made new ones, has been welcomed with a distinct lack of enthusiasm in both the Netherlands and Belgium. As a result, the Genootschap Onze Taal (Our Language Society) decided to publish an alternative list, "het witte boekje" ("the white booklet"), which tries to simplify some complicated rules and offers several possible spellings for many contested words. This alternative orthography is followed by a number of major Dutch media organisations but mostly ignored in Belgium.