\documentclass{article}
\usepackage{multirow}
\usepackage{booktabs}
\begin{document}

\begin{tabular}{|l|l|l|l|}
\hline
Column 1 & Column 2 & Column 3 & Column 4 \\
\hline\hline
\multirow{3}{*}{Row 1 Data} & R1C2 Sub1 & R1C3 Sub1 & R1C4 Sub1 \\
\cline{2-4}
 & R1C2 Sub2 & R1C3 Sub2 & R1C4 Sub2 \\
\cline{2-4}
 & R1C2 Sub3 & R1C3 Sub3 & R1C4 Sub3 \\
\hline
\multirow{3}{*}{Row 2 Data} & R2C2 Sub1 & R2C3 Sub1 & R2C4 Sub1 \\
\cline{2-4}
 & R2C2 Sub2 & R2C3 Sub2 & R2C4 Sub2 \\
\cline{2-4}
 & R2C2 Sub3 & R2C3 Sub3 & R2C4 Sub3 \\
\hline
\multirow{3}{*}{Row 3 Data} & R3C2 Sub1 & R3C3 Sub1 & R3C4 Sub1 \\
\cline{2-4}
 & R3C2 Sub2 & R3C3 Sub2 & R3C4 Sub2 \\
\cline{2-4}
 & R3C2 Sub3 & R3C3 Sub3 & R3C4 Sub3 \\
\hline
\end{tabular}

\end{document}