The paper gives a historical overview, and a summary of key findings from 70 previously published research papers giving scientific data over the years from 1980 to 2019. They concern the flora and/or fauna in the mangrove forests along the Sri Lankan coast, addressing diversity, taxonomy, distribution, and ecological interactions. A total of 28 mangrove floral species from 13 plant families have been reported so far. Similarly, faunal diversity studies have reported 99 invertebrates, dominated by Arthropoda (n = 55) and Mollusca (n = 26), and 214 vertebrates comprising Pisces (n = 112), Aves (n = 72), Reptilia (n = 13) and Amphibia (n = 2). Most studies have been concentrated on the Southwestern coast (nflora = 20, nfauna = 6). Negombo has been a hotspot for mangrove research, with a higher number of studies (nflora = 11, nfauna = 5). The majority of the mangrove studies were focused on mangrove floral diversity and taxonomy and were conducted over recent years (2010–2019). Scientific data on mangrove fauna is restricted to a certain geographical extent. This paper intends to identify the research gaps in the field of Sri Lankan mangroves regarding various aspects and suggests advancement in future studies. Overall, outputs from the present study would be helpful for upcoming researchers to focus more on filling the gaps in knowledge.