Mental-illness-related stigma not only exists in the public but also in healthcare systems. Healthcare providers (HCPs) who have stigmatizing attitudes or behaviors might be thought of as a key barrier to mental health service use, and influence the quality of healthcare. Although cumulative projects have been conducted to reduce stigma related to mental illness among HCPs around the world, little is known about whether the attitudes of HCPs toward mental illness have changed over time. Research on this topic is mixed with respect to whether attitudes of HCPs toward mental illness have become more or less positive. The aim of the current study was to help clarify this issue using a cross-temporal meta-analysis of scores on the Social Distance Scale (SDS), Opinions about Mental Illness (OMI), and Community Attitudes towards Mental Illness (CAMI) measures among health care professionals and students (N = 15,653) from 1966 to 2016. Our results indicated that both social distance (β = −0.32, p < 0.001) and attitudes (β = 0.43, p = 0.007) of HCPs toward mental illness have become increasingly positive over time. These findings provide empirical evidence to support that the anti-stigma programs and courses have positive effects on HCPs and can inform future anti-stigma programs focusing on improving the attitudes of HCPs toward mental illness, thereby improving the quality of healthcare provided.