The paper examines the conditions under which firms enter into technology development partnerships with customers, suppliers and other firms. Three conceptual approaches to inter-firm collaboration are examined, namely: transactions costs theory; resource-strategy theories of the firm; and network theory. Drawing upon data collected in a mailed questionnaire survey of US manufacturing establishments in the chemical, electronics and instruments industries, I assess empirically various determinants of inter-firm collaboration in technology development. The empirical work suggests that large firms, and firms located in major urban centres, are more likely to enter into technology development partnerships. Firms located in a specialized industrial agglomeration do not demonstrate a greater propensity toward entering into technology development partnerships with customers, suppliers or other firms.