Californians for Population Stabilization (CAPS) is a center-left nonprofit that advocates for policies that restrict immigration to the United States from an environmentalist and population-control viewpoint. The organization runs television advertisements, polls, and events to work towards lowering the number of immigrants to California. 
Californians for Population Stabilization was founded in Ventura, California, in 1986 with the goal of minimizing future population growth in California. It started as a branch of the organization Population Connection (formerly Zero Population Growth).  CAPS supports immigration policies reducing the number of immigrants allowed to enter the United States each year. The group holds immigration policy and the federal government, rather than immigrants themselves, are to blame for rising population.
The group alleges that population increase can lead to a strain on California’s environment and infrastructure. CAPS puts an emphasis on the idea that we can only take in the amount of immigrants that our environment and resources can adequately accommodate. 
Californians for Population Stabilization holds that the approach that a rapid expansion in California’s population can hurt the state, both environmentally and socially.
The organization argues that negative consequences of an influx of people are increased pollution levels, damaged natural environments, increased traffic, overcrowded schools, job competition, and higher taxes. CAPS advocates for tightening border protection, increasing deportation, slowing the rate of legal immigration, and eliminating birthright citizenship. 
CAPS has criticized many Republicans favoring moderate immigration reform which would not slow the rate of immigration into the U.S., including Rep. Kevin McCarthy (R-CA), former Sen. Jeff Flake (R-AZ), Sen. Marco Rubio (R-FL), former Sen. John McCain (R-AZ), and former Speaker of the House Rep. Paul Ryan (R-WI). 
CAPS has also targeted President Donald Trump, putting out television advertisement campaigns criticizing him for supporting advancements in legal immigration. 
CAPS has received $7,971,720 in grants since 1999. The Colcom Foundation, an private foundation that funds environmentalist and population control organizations, provided 76 percent of these grant dollars.  The funds for CAPS had been slowly growing and net assets eventually peaked at $1,589,336 in 2012.  In its most recent IRS filing from 2017, CAPS had total revenues of $907,807, total expenses of $1,077,031, and net assets of $560,002. 
Jo Wideman is the group’s executive director, according to tax records and according to her personal LinkedIn.  Wideman received total compensation of $136,294 in 2017.  Wideman holds an extensive background which includes work with the American Red Cross and various technology companies. 
Ben Zuckerman is president of the CAPS board of directors and an astrophysicist, author, and professor at UCLA. Zuckerman also co-edited a book in 1995 titled, “Human Population and the Environmental Crisis.” 
Judith Smith is vice-president of the CAPS board of directors, holding a background consisting of work with the National Charity League, the Los Positas Park Foundation, and the Cottage Hospital Rehabilitation Foundation. 
Ric Oberlink is a former executive director. He held the position from 1992 to 1997, prior to operating as a self-employed consultant to various nonprofits, reportedly including CAPS.