Traffic congestion is a persistent problem in large metropolises and increasingly common in medium and large cities. Several studies have analyzed the negative effects of congestion in terms of economic productivity loss, increased environmental pollution, and negative health consequences. However, less attention has been given to the impact of congestion on the population’s ease of accessing job opportunities, and which income groups are most affected by congestion. This study estimates the impacts of congestion on access to job opportunities in the twenty largest cities in Brazil and examines how people of different income levels and neighborhoods are impacted by congestion. The study compares the number of jobs accessible by car within a 15 to 45 minute travel time interval during the morning peak period and in free-flowing traffic, based on historical information about traffic speeds from high-resolution GPS data. The results show that the municipalities of São Paulo (São Paulo), Rio de Janeiro (Rio de Janeiro), and Brasília (Distrito Federal) have the highest levels of congestion, causing an average reduction in the number of accessible jobs between 40.7% and 24.6%. Meanwhile, the municipalities of Goiânia (Goiás), Campo Grande (Mato Grosso do Sul), and São Gonçalo (Rio de Janeiro) are the least impacted by congestion (with a reduction between 3.2% and 0.6% in job accessibility). People with low income tend to be the most affected, experiencing a decrease of more than 50.0% in the number of accessible jobs during peak time compared to free-flowing traffic. The results raise implications for policies aimed at reducing the inequalities in the impacts of congestion on access to job opportunities, and can inform municipal transportation, housing, and land-use plans.