A Toeplitz operator 𝑇 𝜑 , 𝜑 ∈ 𝐿 ∞ (𝕋 𝑛 ), is a partial isometry if and only if there exist inner functions 𝜑 1 , 𝜑 2 ∈ 𝐻 ∞ (𝔻 𝑛 ) such that 𝜑 1 and 𝜑 2 depends on different variables and 𝜑 = φ1 𝜑 2 . In particular, for 𝑛 = 1, along with new proof, this recovers a classical theorem of Brown and Douglas. We also prove that a partially isometric Toeplitz operator is hyponormal if and only if the corresponding symbol is an inner function in 𝐻 ∞ (𝔻 𝑛 ). Moreover, partially isometric Toeplitz operators are always power partial isometry (following Halmos and Wallen), and hence, up to unitary equivalence, a partially isometric Toeplitz operator with symbol in 𝐿 ∞ (𝕋 𝑛 ), 𝑛 > 1, is either a shift, or a co-shift, or a direct sum of truncated shifts. Along the way, we prove that 𝑇 𝜑 is a shift whenever 𝜑 is inner in 𝐻 ∞ (𝔻 𝑛 ).

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