This study investigates to what extent the intensity of informal care provision has changed during the first lockdown due to the COVID-19 pandemic in the spring of 2020 in the Netherlands, whether these changes differed by the living situation of the care recipient, and whether these changes were associated with changes in indicators for ‘being able to’, ‘have to’ and ‘want to’ provide care (determinants of the Informal Care Model). We collected data in July 2020 among informal caregivers aged 78 and younger who indicated to provide care in March 2020 in the LISS-panel (N = 1,270 care situation of 1,014 caregivers). We found that, on average, informal care provision was reduced during the lockdown; caregivers of care recipients living in care institutions were the most likely to reduce or stop caregiving, and caregivers who helped someone in their own household were most likely to have increased their intensity. Feeling less restricted by the corona measures reduced the likelihood to stop or lower care provision and increased the likelihood of increasing care; being confronted with a reduction of formal care for the care recipient was related to a higher likelihood of increasing care; and stronger concerns about the care recipient increased the likelihood of intensifying care and prevented from stopping or reducing care. We conclude that the COVID-19 measures significantly impacted the amount of informal care provision and that the Informal Care Model provides a useful basis for explaining changes in informal care intensity.