We combine earthquake spectra from multiple studies to investigate whether the increase in stress drop with depth often observed in the crust is real, or an artifact of decreasing attenuation (increasing Q) with depth. In many studies, empirical path and attenuation corrections are assumed to be independent of the earthquake source depth. We test this assumption by investigating whether a realistic increase in Q with depth (as is widely observed) could remove some of the observed apparent increase in stress drop with depth. We combine event spectra, previously obtained using spectral decomposition methods, for over 50,000 earthquakes (M0 to M5) from 12 studies in California, Nevada, Kansas and Oklahoma. We find that the relative high‐frequency content of the spectra systematically increases with increasing earthquake depth, at all magnitudes. By analyzing spectral ratios between large and small events as a function of source depth, we explore the relative importance of source and attenuation contributions to this observed depth dependence. Without any correction for depth‐dependent attenuation, we find a systematic increase in stress drop, rupture velocity, or both, with depth, as previously observed. When we add an empirical, depth‐dependent attenuation correction, the depth dependence of stress drop systematically decreases, often becoming negligible. The largest corrections are observed in regions with the largest seismic velocity increase with depth. We conclude that source parameter analyses, whether in the frequency or time domains, should not assume path terms are independent of source depth, and should more explicitly consider the effects of depth‐dependent attenuation. Plain Language Summary The stress release (or stress drop) during an earthquake provides information about the energy budget, and the slip and area of rupture, which are needed to investigate earthquake triggering and rupture dynamics. Stress drop is also an important element of seismic hazard forecasting since high stress drop earthquakes radiate more high frequency energy, resulting in stronger ground shaking. As depth increases in the earth, the stress on faults increases because of the increased weight of the rocks above. Therefore, many models predict that deeper earthquakes should have higher stress drops. Deeper earthquakes radiate more high frequency energy than shallow ones, and some studies have interpreted this as an increase in stress drop with depth. However, attenuation of seismic energy as the waves travel through the earth is also depth‐dependent, and this is rarely explicitly included in analyses. We perform a combined analysis of frequency spectra from over 50,000 previously studied earthquakes. We compare ratios of large to small magnitude earthquakes, from different depth ranges, to separate the effects of depth‐dependent source radiation from depth‐dependent attenuation. We find that depth‐dependent attenuation can have a first‐order effect and account for much of the previously reported apparent increase in stress drop with depth. Key Points A stacked spectral ratio approach can separate depth dependence of source and path effects Analyses of spectral decomposition inversions suggest that previous reports of increase in stress drop with depth may be overstated Source parameter analyses should explicitly include depth‐dependent attenuation models or empirical corrections