This is a partial and incomplete list of wildfires in the US state of California. California has dry, windy, and often hot weather conditions from spring through late autumn that can produce moderate to severe wildfires. Pre-1800, when the area was much more forested and the ecology much more resilient, 4.4-11.9 million acres (1.8-4.8 million hectares) of forest and shrubland burned annually. California land area totals 99,813,760 or roughly 100 million acres, so since 2000, the area that burned annually has ranged between 90,000 acres, or 0.09%, and 1,590,000 acres, or 1.59% of the total land of California. During the 2020 wildfire season alone, over 8,100 fires contributed to the burning of nearly 4.5 million acres of land.

The timing of "fire season" in California is variable, depending on the amount of prior winter and spring precipitation, the frequency and severity of weather such as heat waves and wind events, and moisture content in vegetation. Northern California typically sees wildfire activity between late spring and early fall, peaking in the summer with hotter and drier conditions. Occasional cold frontal passages can bring wind and lightning. The timing of fire season in Southern California is similar, peaking between late spring and fall. The severity and duration of peak activity in either part of the state is modulated in part by weather events: downslope/offshore wind events can lead to critical fire weather, while onshore flow and Pacific weather systems can bring conditions that hamper wildfire growth.

Climate change in California has lengthened the fire season and made it more extreme from the middle of the 20th century.

Since the early 2010s, wildfires in California have grown more dangerous because of the accumulation of wood fuel in forests, higher population, and aging and often poorly maintained electricity transmission and distribution lines, particularly in areas serviced by Pacific Gas and Electric. United States taxpayers pay about US$3 billion a year to fight wildfires, and big fires can lead to billions of dollars in property losses. At times, these wildfires are fanned or made worse by strong, dry winds, known as Diablo winds when they occur in the northern part of the state and Santa Ana winds when they occur in the south. However, from a historical perspective, it has been estimated that prior to 1850, about 4.5 million acres (17,000 km²) burned yearly, in fires that lasted for months, with wildfire activity peaking roughly every 30 years, when up to 11.8 million acres (47,753 km³) of land burned. The much larger wildfire seasons in the past can be attributed to the policy of Native Californians regularly setting controlled burns and allowing natural fires to run their course, which prevented devastating wildfires from overrunning the state. There are conservation issues that prevent some controlled burns necessary to lessen the damage for when a wildfire starts.

More than 350,000 people in California live in towns sited completely within zones deemed to be at very high risk of fire. In total, more than 2.7 million people live in "very high fire hazard severity zones", which also include areas at lesser risk.

On lands under CAL FIRE's jurisdictional protection (i.e. not federal or local responsibility areas), the majority of wildfire ignitions since 1980 have been caused by humans. The four most common ignition sources for wildfires on CAL FIRE-protected lands are, in order: equipment use, powerlines, arson, and lightning.

A 2023 study found that these wildfires are affecting the California ecosystem and disrupting the habitats. It found that in the 2020 and 2021 fire seasons 58% of the area affected by wildfires occurred in those two seasons since 2012. These two fires destroyed 30% of the habitat of 50 species as well as 100 species that had 10% of their habitats burn. 5-14% of the species' habitats burned at a "high severity."

Starting in 2001, the National Interagency Fire Center began keeping more accurate records on the total fire acreage burned in each state.