The ability to borrow is anchored on an organization to raise required collateral security, cash flow, profitability, firm size, among others. There has not been any consensus on the influence of firm financial characteristics on leverage since some have positive, negative, significant and non-significant influences on leverage. Moreover, most studies have been considering all listed companies in the absence of time-invariant characteristics and specific risk considerations that vary from listing sectors. Hence, the current study examined the influence of firm financial characteristics on the leverage of listed commercial and allied companies in Nairobi securities exchanges. Specifically, the study examined the effect of tangibility of assets, profitability, firm size, and growth opportunities on leverage. Moreover, the moderating effect of operating cash flows was examined. The study was based on the pecking order theory. Secondary data were collected for the period 2008-2016. Data was analyzed using univariate, bivariate and multivariate techniques. Study findings indicated tangibility of assets and growth opportunities has an inverse and significant influence on leverage. Profitability has a positive and not significant influence on leverage. Firm size has an inverse and not significant influence on leverage. Moreover, operating cash flow has a moderating effect on the influence of firm financial characteristics on the short leverage of listed commercial and services firms in Nairobi securities exchange. Listed companies should consider exploration of opportunities that would maintain significant co-movement between firm financial characteristics and leverage of listed commercial and allied companies in Nairobi securities exchange. The management of Nairobi securities exchanges and capital market authority ought to develop measures to recruit more companies to be listed to enhance the odds of access to finance.