Kaspersky has quit anti-piracy group the Business Software Alliance (BSA) over its support of the US Stop Online Piracy Act (SOPA).
The Russian security firm would not renew its membership next year even though the BSA has something of a mixed stance on the SOPA legislation.
SOPA could ask ISPs to monitor traffic and potentially block access to websites that are breaking copyright law.
"Kaspersky Lab is occasionally mentioned in the discussion as a member of the Business Software Alliance, which supports the SOPA initiative," Kaspersky said.
"Kaspersky Lab would like to clarify that the company did not participate in the elaboration or discussion of the SOPA initiative and does not support it.
"Moreover, the company believes that the SOPA initiative might actually be counter-productive for the public interest, and decided to discontinue its membership in the BSA as of 1 January 2012.
The BSA said it shared some views of the security giant on SOPA.
"We are very disappointed to learn that Kaspersky Lab may not renew their membership in BSA, especially given we share many of their concerns over SOPA," BSA government relations vice president Katherine McGuire said.
"Kaspersky has been a valued member of BSA over the past two years, and we look forward to working with them again in the future."
BSA voiced concerns over SOPA in November after previously supporting the initiative.
"[SOPA] could sweep in more than just truly egregious actors," the BSA said in a blog post.