The LaTeX command for sqsubseteq (⊑) is \sqsubseteq.
\sqsubseteqWriting a paper? The table generator and the BibTeX cleaner are one click away, no account.
Write \sqsubseteq inside math mode, that is between $…$ for inline math or in a \[ … \] or equation block for display math. It is part of core LaTeX math, so no extra package is required.
As a relation, \sqsubseteq gets a thick space on each side, and a long inline formula may break after it. With unicode-math under XeLaTeX or LuaLaTeX, typing ⊑ in a formula gives the same symbol.
$a \sqsubseteq b$Open this example in the live preview: it renders as you type, with no compiler and no signup.
Relation symbols in LaTeX: the full table or search all 350+ LaTeX symbols.
Use \sqsubseteq in math mode; it needs no extra package. For example, $a \sqsubseteq b$.
None: \sqsubseteq is built into LaTeX, so no extra package is required.