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<jats:title>ABSTRACT</jats:title> <jats:p>We evaluate two dominant nuclear reaction rates and their uncertainties that affect <jats:sup>44</jats:sup>Ti production in explosive nucleosynthesis. Experimentally we develop thick target yields for the <jats:sup>40</jats:sup>Ca(α, γ)<jats:sup>44</jats:sup>Ti reaction at <jats:italic>E</jats:italic> <jats:sub>α</jats:sub> = 4.13, 4.54, and 5.36 MeV using γ-ray spectroscopy. At the highest beam energy, we also performed an activation measurement which agrees with the thick target result. From the measured yields a stellar reaction rate was developed that is smaller than current statistical-model calculations and recent experimental results, which would suggest lower <jats:sup>44</jats:sup>Ti production in scenarios for the α-rich freezeout. Special attention has been paid to assessing realistic uncertainties of stellar reaction rates produced from a combination of experimental and theoretical cross sections. With such methods, we also develop a re-evaluation of the <jats:sup>44</jats:sup>Ti(α, <jats:italic>p</jats:italic>)<jats:sup>47</jats:sup>V reaction rate. Using these two rates we carry out a sensitivity survey of <jats:sup>44</jats:sup>Ti synthesis in eight expansions representing peak temperature and density conditions drawn from a suite of recent supernova explosion models. Our results suggest that the current uncertainty in these two reaction rates could lead to as large an uncertainty in <jats:sup>44</jats:sup>Ti synthesis as that produced by different treatments of stellar physics.</jats:p>