Vences et al. (2004) confirmed the validity of Hemidactylus mercatorius as a species distinct from H. mabouia, with which it had previously been confused, considering that it represented mainland African and Madagascan members of this species complex. Uncertainty over the exact definitions of these two species, and potential confusion with additional species of Hemidactylus, remain, making it difficult to establish the global distribution of either H. mercatorius or H. mabouia. Vences et al. (2004) found that Madagascan H. mercatorius were genetically distinct from a sample from Mozambique. Within Madagascan H. mercatorius, at least three distinct lineages appear to exist (Vences et al. 2004, Boumans et al. 2007). Rocha et al. (2005) found that Gulf of Guinea "H. mabouia" identified by Jesus et al. (2005) belonged to the northern Madagascar lineage of H. mercatorius identified by Vences et al. (2004). This concept of H. mercatorius as a widespread island species appears to correspond to Clade A of the H. mabouia-mercatorius complex identified by Rocha et al. (2010), which is also found in Tanzania, South Africa (where three separate lineages have been identified), Uganda, the Seychelles, including a lineage endemic to the Aldabra archipelago, and Réunion (Sanchez et al. 2012). However, given the apparent basal relationships of mainland African members of this clade and continuing uncertainty over their taxonomic assignment, this assessment follows Rocha et al. (2010) in restricting the name H. mercatorius to island populations within this clade, with continental populations remaining under the name H. mabouia until the taxonomy of this species complex is resolved. This treatment is acknowledged as being "completely inadequate" (Rocha et al. 2010) as East African coastal populations alone exhibit substantial variation both between and within several recognized major lineages, and the taxonomy of this species complex, and clarification of the mainland African range of H. mercatorius, is in need of further resolution. Based on current understanding, Clade A of H. mercatorius also appears to represent introduced populations in South America and Cape Verde traditionally referred to H. mabouia (Carranza and Arnold 2006, S. Rocha pers, comm. April 2012). Research into the genetics of South American H. mabouia is however preliminary. Only one lineage has so far been identified from Brazil, however there is insufficient data to clarify whether this is the only introduced lineage in the Americas (D. Borges pers. comm. April 2012). Pending resolution of this issue, all Neotropical introductions of this species are referable to H. mabouia (D. Borges pers. comm. April 2012), and this treatment is followed here. Within mainland West Africa, populations of H. mabouia ranging from Senegal to Guinea, Ghana, Togo and Cameroon are genetically similar (J-F. Trape pers. comm. April 2012), but these have not been compared with East African samples and so the relationship between this widespread form and the present concept of H. mercatorius is unclear.

Butler et al. (2019) report that work is ongoing to revise the systematics of the H. mabouia complex, and that this will recognize Hemidactylus benguellensis, presently a junior synonym of H. mabouia (but tentatively recognized as distinct by Marques et al. 2018), as a genetically and morphologically distinct species. This account refrains from accepting this taxonomic change pending the completion of this wider-ranging revision.

Listed as Least Concern on the basis that, as presently understood, this species is very widespread, thrives in human-modified habitats, occurs in large numbers, and is not thought to be subject to any threats.

This species is provisionally considered to occur throughout much of mainland sub-Saharan Africa, from western Senegal to East Africa and along the East African coast including Tanzania, Mozambique and South Africa (Trape et al. 2012, Rocha et al. 2010), north at least as far as the Lower Juba region of Somalia (Lanza 1990) and the southern border with Ethiopia (Battersby 1954). Isolated historical records from further north - one from Harar in Ethiopia, and one from Eritrea - are of doubtful reliability (Loveridge 1947, Largen 1997), and it is not included in a checklist to lizards of Ethiopia (Largen and Spawls 2006). These records may instead represent Hemidactylus laticaudatus (S. Spawls pers. comm.). Indian Ocean subpopulations, and those from the Gulf of Guinea, are presently assigned to H. mercatorius (Rocha et al. 2010), as are those now known from several islands in the Cape Verde archipelago (Vasconcelos et al. 2013).

Records of this species from the Antilles (Netherlands Antilles, Bahamas, Cuba, Jamaica, Grand Cayman, Puerto Rico, Virgin Islands, and the Lesser Antilles), Trinidad and Tobago, and coastal areas of the American tropics are considered to represent introductions (A. Bauer pers. comm. 2012), and while some of these are likely to represent the form currently known as H. mercatorius (S. Rocha pers. comm. April 2012), they are here retained within H. mabouia pending resolution of the taxonomy of Neotropical introductions. 

In West Africa this species' distribution appears fragmented and centered on towns, particularly ports, probably as a result of competition with the ecologically similar H. angulatus (Trape et al. 2012). It is more widespread in Cameroon and other areas of Central Africa (Trape et al. 2012). As presently defined, H. mabouia occurs throughout most of East Africa and is found in most of the region's permanent settlements, being absent only from dense forest and areas at elevations above 2,100 metres (Spawls et al. 2002), although it can reach 2,500 metres in parts of its range (Spawls et al. 2002). Angolan records of "Hemidactylus benguellensis" are known from Benguella and Huíla Provinces.

In South America this species occurs along the coastal region in Brazil, the Guianas, north-central Venezuela (Rivas 2001); along most of the Amazon River, its head waters in Colombia, Ecuador and Peru, and several of its tributaries; and in some localities in central Brazil. Vanzolini (1978b) discussed the distribution of H. mabouia in continental South America. He suggested that the southern limit of the species is probably Rio Grande do Sul, doubting an existing record for the species in Uruguay; he also suggested that the species is associated with relatively wet climates, which would explain its scarce presence in central Brazil, largely covered by 'cerrados', with drier conditions than in forested areas (Avila-Pires 1995). However, Carreira et al. (2005) confirmed its presence in Rivera, Uruguay. The presence of juveniles suggests that there is a stable population there (Carreira et al. 2005). There are also occasional records from Montevideo (Carreira et al. 2005). There are also records from Argentina (Baldo et al. 2008) and Paraguay (Baldo et al. 2008, Cacciali and Motte 2009).

This species occurs in large numbers in towns (Trape et al. 2012). It is probably the most commonly seen gecko in East Africa, being most abundant along the East African coast from Somalia to Mozambique (Spawls et al. 2002).

In West Africa, this species is exclusively found in or around areas of human habitation in towns and villages (Trape et al. 2012), where it is active both by day and night but is mostly seen at night waiting near electric lights to ambush insect prey (Trape et al. 2012). Elsewhere it occurs in a wide range of natural habitats from semi-desert and dry savannah to miombo woodland and evergreen bushland (Spawls et al. 2002). Shelter sites include trees with loose bark, palms, rock crevices and caves (Spawls et al. 2002). In South America it is mainly found in perianthropic situations, on internal and external walls of buildings, on street poles, etc. (Avila-Pires 1995, Cacciali and Motte 2009). In Serra do Navio it was also found (at night) on isolated trees, in the garden around some buildings, and running through grass and leaves on ground, between the buildings and trees (Avila-Pires 1995). According to Vanzolini (1978), Hemidactylus. mabouia has also been found in environments subject to very little disturbance, suggesting that it can colonize natural environments. It is an oviparous species, laying clutches of two eggs.

It is unlikely that this widespread human commensal is subject to any threats.

There is no use or trade in this species.

Following the recognition of Hemidactylus mercatorius as a valid species distinct from H. mabouia. further research is required to clarify the taxonomy of this species complex and the distribution of its component species. No conservation measures are required. It is presumably present in numerous protected areas.