Mozilla announced the resignation in a blog posting in which it said that its "organisational culture reflects diversity and inclusiveness.
"Eich came under fire last month when numerous websites, including the popular dating site OK Cupid, urged users to boycott Firefox after it was revealed that Eich had donated thousands of dollars to Proposition 8, a 2008 constitutional amendment in California that disallowed same sex marriages.
The amendment has since been rejected by federal courts as violating the US Constitution.
DPA