The influence of certain factors on organizational structure has been in researchers’ focus for years, together with their impact on the overall organizational efficiency. Many of these factors are from the environment where traditional view commonly divided into internal and external factors. This paper presents the findings of a study to evaluate the influencing factors and impact on organizational structure of a sample of firms located in Hanoi, Vietnam. Structured questionnaires were administered with respect to these factors. The variables studied were identified from among the factors considered in contingency theory and by incorporating elements of the strategic choice approach. After grouping the variables into two factors (related to external and internal respectively), the results revealed three groups of firms according to how they regarded the impact of these factors on organizational structures. In those groups that consider the variables of internal factors to be modifiers of structure the organizational structures are of the “complex classical” type, whereas simple forms predominate in the group that believes these variables do not modify their structure.
 L. J. Bourgeois, D. W. McAllister and T. R. Mitchell, “The Effects of Different Organizational Environments upon Decisions about Organization Structure,” Academy of Management Journal, Vol. 21, No. 3, 1978, pp. 508-514. doi:10.2307/255732
 L. G. Hrebiniak and C. C. Snow, “Industry Differences in Environmental Uncertainty and Organizational Characteristics Related to Uncertainty,” Academy of Management Journal, Vol. 23, No. 4, 1980, pp. 750-759. doi:10.2307/255561
 L. Gordon and V. K. Narayanan, “Management Accounting Systems, Perceived Environmental Uncertainty, and Organizational Structure: An Empirical Investigation,” Accounting, Organizations and Society, Vol. 9, No. 1, 1984, pp. 33-47. doi:10.1016/0361-3682(84)90028-X
 R. E. Walton, “From Control to Commitment: Transforming Work Force Management in the US,” In: K. Clark, R. Hayes and C. Lorenz, Eds., The Uneasy Alliance: Managing the Productivity-Technology Dilemma, Harvard Business School Press, Boston, 1985, pp. 237-265.
 “The Role of Organizational Structure in an Organization,” 2012. http://www.fao.orgdocrep/005
 D. Wolf, “Execution and Structure,” 2002. http://www.dewarsloan.com/workin%20papers-execution %20and20%structure.html
 “Dictionary-Organizational Behavioral,” 2012. http://www.ivey.uwo.ca/intlstudentsdictionary/OBdic. html
 C. J. Sablynski, “Foundation of Organizational Structure,” 2012. http://www.csus.edu/indiv/s/ sablynskic/ch.14.html
 J. E. Skivington and R. L. Daft, “A Study of Organizational Frame Work and Process Modalities for the Implementation of Business-Level Strategic Decisions,” Journal of Management Study, Vol. 28, No. 1, 1991, pp. 45-68.
 R. Underdown, “Organizational Structures,” 2012. http://dept.lamar.edu/industrial/underdown/ org_mana/org/org_structure-George.html
 D. C. Andrews, “Is There an Organizational Structure for Our Reengineering Business Operation?” Enterprise Reengineering, 2012. http://www.efenselink.mil/c3ibpr/prcd 5280.html
 R. Dewar and J. Werbel, “Universalistic and Contingency Predictions of Employee Satisfaction and Conflict,” Administrative Science Quarterly, Vol. 24, No. 3, 1979, pp. 426-448. doi:10.2307/2989921
 R. Germain, “The Role of Context and Structure in Radical and Incremental Logistics Innovation Adoption,” Journal of Business Research, Vol. 35, 1996, pp. 117-127. doi:10.1016/0148-2963(95)00053-4
 W. Zheng, B. Yang and G. N. Mclean, “Linking Organizational Culture, Strategy and Organizational Effectiveness; Mediating Role of Knowledge Management,” Journal of Business research, Vol. 63, No. 7, 2010, pp. 763-771. doi:10.1016/j.jbusres.2009.06.005
 C. C. Liao et al., “How Knowledge Management Mediates the Relation between Environment and Organizational Structure,” Journal of Business Research, Vol. 64, No. 7, 2011, pp. 728-736. doi:10.1016/j.jbusres.2010.08.001
 A. Y. Nahm, et al., “The Impact of Organizational Structure on Time-Based Manufacturing and Plant Performance,” Journal of Operations Management, Vol. 21, No. 3, 2003, pp. 281-306. doi:10.1016/S0272-6963(02)00107-9
 C. J. Chen and J. W. Huang, “How Organizational Climate and Structure Affect Knowledge Management, The Social Interaction Perspective,” International Journal of Information Management, Vol. 27, No. 2, 2007, pp. 104-118. doi:10.1016/j.ijinfomgt.2006.11.001
 O. C. Ferrell and S. J. Skinner, “Ethical Behavior and Bureaucratic Structure in Marketing Research Organizations,” Journal of Marketing Research, Vol. 25, No. 1, 1988, pp. 103-109. doi:10.2307/3172930
 R. Germain, et al., “Supply Change Variability, Organizational Structure and Performance: The Moderating Effect of Demand Unpredictability,” Journal of operations management, Vol. 26, No. 5, 2008, pp. 557-570. doi:10.1016/j.jom.2007.10.002
 J. L. Cheng and W. Mckingley, “Toward an Integration of Organization Research and Practice: A Contingency Study of Bureaucratic Control and Performance in Scientific Settings,” Administrative Science Quarterly, Vol. 28, No. 1, 1983, pp. 85-100. doi:10.2307/2392388
 “What Impacts Organizational Structure?” 2012. http://www.ehow.com/facts_515
 J. J. Brown, “Flattening the Organizational Hierarchy of the Fairfax County, Virginia Fire and Rescue Department,” Executive Fire Officer Program, National Fire Academy, Emmetsburg, Maryland, 1995.
 D. Penguin, “Fundamentals of Organizational Structure,” 2003. http://www.up.univ-mrs.fr/~wlag/ ea/gmba/orgthe/topic2.html
 “The Importance of a Good Organizational,” 2012. http://smallusiness.chron.com/importance-goodorganizational-srtucture
 J. Clemmer, “Organization Structure Limits or Liberates Highperformance,” 2003. http://www. clemmer.net/excerpts/ph_orglimits.html
 “What are the Benefits of Organiaztional,” 2012. http://www.ehow.com/list_6532
 S. Auh and B. Mengue, “Performance Implications of the Direct and Moderating Effects of Centralization and Formalization on Customer Orientation,” Industrial Marketing Management, Vol. 36, No. 8, 2007, pp. 1022-1034. doi:10.1016/j.indmarman.2006.02.010
 Selto, et al., “Assessing the Organizational Fit of a Just-in-Time Manufacturing System-Testing Selection, Interaction and Systems Models of Contingency Theory,” Accounting, Organizations and Society, Vol. 20, No. 7-8, 1995, pp. 665-684. doi:10.1016/0361-3682(95)00022-2