One of the consequences of major regulatory reform of the telecommunications sector from the end of the 1970s - particularly, privatisation, liberalisation and deregulation - was the establishment of a new business environment which permitted former national telecommunications monopolies to expand abroad. From the 1990s, a number of these firms, particularly those based in Europe, joined the rankings of the world's leading multinational corporations. Their internationalisation was uneven, however: while some firms internationalised strongly, others ventured abroad much slower. This article explores how the regulatory framework within which telecommunications incumbents evolved over the long-term shaped their subsequent, uneven, paths to internationalisation. Two case studies representing 'maximum variation' are selected: Telefonica, whose early and unrelenting expansion transformed it into one of the world's most international of multinational corporations, and BT, whose overseas ventures failed and, with eroding domestic market share, forced the firm to partially retreat, becoming the least international of the large European incumbents. Longterm ownership, access to capital, management style and exposure to liberalisation strongly influenced firms' approaches to internationalisation.
