<p>The announcements of pandemic lockdown measures across North America in mid-March 2020 marked the start of a chaotic period with extensive changes at work and at home. Because families experiencing financial strain had fewer resources to help manage work and family demands, the present study examined how financial strain at the within- and between-person levels influenced work interference with family (WIF) and family interference with work (FIW) and whether those experiences were moderated by childcare and eldercare responsibilities. Using a longitudinal panel design, 538 workers recruited through Amazon’s Mechanical Turk responded to seven surveys between April and October 2020 asking about financial strain, WIF, and FIW. Multilevel modeling showed that an individual’s average financial strain over the seven-month period was associated with higher WIF and FIW; however, a higher-than-usual level of financial strain was associated only with higher FIW. Interactions of financial strain with childcare and eldercare were not significant. At the between-person level, financial strain was an important contributor to WIF and FIW, even after accounting for childcare and eldercare. Consistent with conservation of resources theory, these findings suggest that financial strain represents a perceived threat that actively draws on limited personal resources, thereby reducing capacity to manage work-family conflict. This underscores the need for greater support for families experiencing financial strain. In addition to fair pay and benefits, organizations could consider novel approaches to reducing financial strain amongst employees such as financial counselling and emergency income replacement funds. </p>