tex4ht does not support minitoc. And could not make it to work with titletoc either.
One way to simulate it, is to use \TocAt{} inside the document, like this:
pdflatex foo.tex htlatex foo.tex "htm" htlatex foo.tex "htm,2" \documentclass{report}% \usepackage{ifpdf} \usepackage{lipsum} \usepackage{minitoc} \begin{document} \title{test minTOC with tex4ht} \author{me} \date{\today} \maketitle \ifdefined\HCode \else \dominitoc %only for pdf \fi \tableofcontents \ifdefined\HCode \TocAt{chapter,section,subsection} %do it before chapter \fi \chapter{chapter 1} \ifdefined\HCode \else \minitoc \fi \lipsum{1} \section{section 1 under chapter 1} text \subsection{subsection 1 under section 1 under chapter 1} text \subsubsection{subsubsection 1} \ifdefined\HCode \TocAt{chapter} %RESET it to NO TOC before chapter \fi \chapter{chapter 2} \lipsum{1} \section{section 1 under chapter 2} \end{document}