Industry sectors in focus in the studies included eight specific sectors; extractive, tobacco, food, alcohol, pharmaceuticals, weapons, textiles and asbestos (see Fig. 2). We labelled 13 studies ‘general’ as they each encompassed a range of industry sectors. One hundred and thirty-five studies were qualitative, two studies were quantitative, and seven studies used mixed methods.

Number of studies, by industry sector

The majority of studies focused on NGO interactions at the country level (79%), followed by the global (19%) and regional levels (2%) (See Supplementary Table). There was a geographic spread for country-level studies in the extractive, tobacco and food sectors across Africa, Asia, Latin America and Europe (see Fig. 3).

Geographical spread of country studies’ focus

Of the 72 country studies in the extractive sector, 10 were in the US, 7 in Canada and 7 in Nigeria. India (5) and Nepal (3) were the most prevalent country studies for tobacco sector (n = 32), as were Australia (6), Indonesia (4), USA (3), Mexico (3), Canada (3) in the food sector (n = 25). Pharmaceutical studies at the country level included South Africa (n = 3), Guatemala (n = 1), Kenya (n = 1) and Thailand (n = 1), and textile country-level studies included one study on Ghana and India and one study on China, Indonesia, the Philippines, Thailand and USA. Alcohol country level studies focused on Australia (n = 1), Lithuania (n = 1) and Sweden (n = 1); asbestos in China (n = 1); and weapons in the US (n = 1) (see map Fig. 3).

We identified 18 different ‘inside’ and ‘outside’ strategies used by NGOs across sectors to target commercial or government actors (see Table 2). We explain each of these strategies below.

We identified from the studies five types of strategies used by NGOs to directly target commercial actors: 1) partnerships and multistakeholder initiatives; 2) private meetings and roundtables; 3) engaging with company AGMS and shareholders; 4) collaborations other than partnerships, and 5) litigation. 58 studies (40%) reported at least one NGO inside strategy directly targeting commercial actors.

NGOs sought to influence commercial actors directly through the formation of partnerships and multistakeholder platforms – a strategy identified in 18 studies [21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38]. Partnerships included between the World Wildlife Fund and Unilever [28, 33], Coca Cola, Nokia and Hewlett-Packard [34], and environmental NGOs partnerships with British American Tobacco [30]. Partnerships also comprised NGO-commercial-government (and thus encompassed ‘inside’ strategies with government). Five studies examined the monitoring role of NGOs in the Extractive Industries Transparency Initiative (EITI), a partnership between NGOs, commercial actors and governments at the country-level designed to promote transparency in extractive industry governance [27, 29, 35,36,37]. In several studies, engaging in partnerships were reported to be an incremental strategy by NGOs as part of a longer-term campaign for greater regulation of industry practices [22, 29, 35, 36], although some studies found that these partnerships enabled corporate actors to have greater influence on policymaking [30].

A second NGO ‘inside’ strategy was holding private meetings and roundtables with commercial actors, also identified in 18 studies [22, 23, 32, 33, 38,39,40,41,42,43,44,45,46,47,48,49,50,51]. Private meetings have been used by NGOs to attempt to find commercial allies – for example through the formation of private NGO-industry roundtables on reducing fossil fuel emissions [32]. NGOs have also used meetings to target ‘surrogate’ commercial actors in supply chains. Four studies, for example, explored NGOs using private meetings with banks and investors to attempt to influence loans made to extractive companies [33, 48,49,50]. While the majority of studies did not analyse the content of NGO-commercial actor meetings in depth, one study of NGO engagement with extractive industries documented the development of NGO-industry terms of engagement [45].

The third NGO ‘inside’ strategy was engaging with company shareholders, identified in 14 studies [23, 33, 42,43,44, 48, 50, 52,53,54,55,56,57,58]. In the majority of these studies, NGOs spoke at company annual general meetings and company board meetings, and targeted shareholders and investors through statements and shareholder resolutions in an attempt to influence corporate behaviour directly [23, 42,43,44, 48, 52,53,54,55,56, 58]. Two studies outline further NGO engagement, including briefing, consulting and advising shareholders, becoming shareholders themselves, and creating mutual funds to influence a range of investors [55, 56]. Four studies explored a transnational dimension to shareholder engagement through which NGOs from low income countries used their networks to speak at shareholder and company meetings in the US [57], Canada [23], Australia [50], and France [33].

A fourth NGO ‘inside’ strategy was collaborations other than formalised partnerships, identified in 13 studies [21, 22, 45, 53, 59,60,61,62,63,64,65,66,67]. Commercial actor-NGO collaborations included collaborations on sustainability standards [62, 64], reducing food waste (for example, between NGOs and McDonald’s) [59], participation in CSR initiatives [66] and collaborating on reports – for example reports produced by Oxfam and Unilever [22]. Informal collaborations between NGOs and media organisations were documented in 4 studies, where NGOs provided training to journalists of media organisations on monitoring tobacco industry practices [60, 61, 67] and childhood nutrition and infant feeding [68].

Finally, NGO litigation directly against a commercial actor was a common strategy in 20 studies [22, 23, 41, 48, 50, 52, 69,70,71,72,73,74,75,76,77,78,79,80,81,82]. Unlike litigation against government (see below), this strategy focused on litigating directly against an commercial actor. In South Africa, NGO litigation against pharmaceutical firms over lack of access to HIV/AIDS treatment has resulted in the companies being found guilty of abusing antitrust law [77]. In India, NGOs filed public interest cases against mining giant Rio Tinto on charges of illegal mining, leading to temporary moratoriums on mining practices [78]. Litigation has also been used by NGOs against media companies and advertising firms over the broadcasting of cigarette advertising [82]. Three studies reported on a transnational dimension to NGO litigation where networks filed suits where TNCs were headquartered – for example litigation against Shell in the UK [75, 76] and US [76], and in Canada against transnational mining firms on behalf of NGOs in Latin America and Africa [79]. We classified litigation as ‘inside’ because it represents an attempt to directly influence a commercial actor, thoug