This dissertation is concerned with the spatial dimensions of tourism and related physical planning issues, focusing on Greece. It explores relevant research in this area, analyses the structure of tourism at different spatial levels, and relates tourism's spatial structure to planning parameters. Within the W.European context, tourism's growth and spatial structure reflects a process of leisure division (tourism demand and consumption differentiation) attributed to (i) marked inter-country differences regarding socioeconomic, supply-attraction and accessibility factors, and (ii) the international organization of the tourist industry: the influential role of tour operators and airlines in controlling market size, price of the tourist product (TP), and transport links. Tourism's spatial structure in Greece is influenced by both endogenous and exogenous factors: (i) the country's socioeconomic development process, territorial structure and regional accessibility, and the organizational mode of the Greek tourist industry and relevant government policies (investments), and (ii) the way Greek regions are connected with the international travel system, and are affected by tour operations; the latter, building on existing locational advantages, and reinforcing development in "established" places. Physical planning, confined within a legalistic frame of restrictive measures, is weakly related to economic and sectoral planning; negatively affected by administrative-institutional constraints (inadequate planning system, legal-statutory frame, planning organization); ineffectively integrated into a planning process characterized by limited political commitment to, and social awareness and acceptability of planning action. The ineffectiveness of tourism and physical planning to influence endogenous or exogenous factors, underlying tourism's spatial structure, is evidenced by the absence of any substantial rapport between the kind of physical development taking place, and concurrent planning practices. The advanced "territorial profiles" and tourist policy proposals provide: (i) a methodological frame, conceptualizing tourism's organization on a territorial basis, for interrelating and integrating economic, sociocultural and physical dimensions in tourist development planning, and (ii) a planning guidelines-frame suggesting the main policy directions for TP and market restructuring, and for improving physical and tourism planning practice in Greece.