Freedom of speech did not mean an "open season" on religious taboos, he said.
In London, hundreds of British Muslim protesters gathered outside the Danish embassy. It was in a Danish newspaper the controversial cartoons first appeared.
Among the images -- which have sparked protest across the Muslim world -- is one of the Propher Mohammed with a turban-shaped bomb on his head. Images of Mohammed or Allah are prohibited by Islam.
The editor of the Danish paper Jyllands-Posten which first carried them in September has apologized. However newspapers and magazines in Norway, Spain, Italy, Germany, Hungary and France have since reprinted the material in a demonstration of free expression.
Speaking at a London news conference after talks with the Sudanese foreign minister, Straw said: "I believe that the republication of these cartoons has been insulting, it has been insensitive, it has been disrespectful and it has been wrong."
In some countries, protests have turned violent.
On Monday, gunmen surrounded the European Union's offices in Gaza, while in the Indonesian capital, Jakarta, protesters stormed the lobby of the Danish embassy.
In London, some protesters bore placards with violent messages, including: "Europe you will pay, Bin Laden is the way" and "Behead those who insult Islam."