Marianne Thieme is a Dutch politician and co-founder of Party for the Animals (Partij voor de Dieren), a political party standing for animal rights and animal welfare. A jurist by education, Thieme became a vegetarian and started to campaign for animal rights during her student days. Along with other animal protectionists, she started the Party for the Animals in 2002.

From its inception, the party steadily gained voters, eventually obtaining two seats in the House of Representatives of the Netherlands in the Dutch general elections in 2006, becoming the first party in the world to represent animal rights in parliament. Thieme was chosen as the party's parliamentary leader. In 2014, the party got over 4% of votes for the European Parliament election, which was enough for a seat in the European Parliament.

Party for the Animals has already achieved noticeable results in the Netherlands, from enforcement of stricter video monitoring in slaughterhouses and live markets to securing public funding for the development of meat substitutes. They convinced the majority of the parliament to agree with them to outlaw the slaughter of animals without stunning. Their successes have also inspired the formation of many more animal parties throughout the world. Their stated long-term goals are to end the treatment of animals as economic products, to abolish factory farming, and to achieve a better society.

Thieme criticises modern society's lack of compassion and sustainability, and links the troubles of our time – the economic crisis, climate change and widespread starvation – to greed and short-term human interests. She warns that if humanity does not change its attitude towards animals and nature, the consequences for future generations will be dire. However, she is an optimist, and predicts that through the efforts of people who share her vision, this will happen within 50 years.