Abstract: This thesis covers several issues on fiscal policy behavior, business cycle fluctuations, and labor market outcomes. It goes beyond of the standard axioms by taking the informal economy as a source for shaping economic fluctuations. In fact, several macroeconomic implications of the informal economy link the three, rather independent, essays. Chapter 2 performs a systematic review of the literature on the cyclical behavior of fiscal policy along three dimensions: (i) the set of theories, (ii) measurement of cyclicality of fiscal policy, and (iii) empirical evidence. We observe that fiscal procyclicality in developing countries is a broad regularity whereas fiscal policy is generally countercyclical or acyclical in more developed countries. We find that 36.3% of developed countries follow countercyclical fiscal policy while only 3.5% of developing countries follow such policy pattern. Credit constraints and political economy factors are usually taken to account for fiscal procyclicality, but empirically they explain such procyclicality only about 33.5% and 30.3%, respectively. We argue that the informal sector may also be an explanation in determining fiscal procyclicality; but, to the best of our knowledge, the literature fails to cover for this relationship. Chapter 3 provides a set of business cycle regularities on the informal sector. We estimate the size of the informal sector for 105 countries and summarize the findings with 10 stylized facts and 5 corollaries. We arrive at three key conclusions. First, the size of informal sector is procyclical. Second, informal sector is linked to volatility of GDP. Third, informal sector is positively associated to procyclicality of fiscal policy. Chapter 4 builds a small, open, developing economy DSGE model. It considers three alternative scenarios for financial integration under dual labor market segments. We find that perfectly integrated economies react more smoothly to shocks. We also find that both imperfections on credit markets and the size of the informal sector stand up as sources of volatility in output and increase the degree of procyclical government consumption. The model suggests that external finance premium and the informal sector (which behaves procyclically) work under a complementary relationship. Chapter 5 concludes and provides policy prescriptions and the path for future research.