diff --git a/src/Utilities/matrix_of_constraints.jl b/src/Utilities/matrix_of_constraints.jl
index cee2305cc1..451b6e9ef7 100644
--- a/src/Utilities/matrix_of_constraints.jl
+++ b/src/Utilities/matrix_of_constraints.jl
@@ -525,8 +525,35 @@ end
 
 function_constants(b::Vector, rows) = b[rows]
 
-# FIXME does not work for all sets
-set_from_constants(::Vector, ::Type{S}, rows) where {S} = S(length(rows))
+function set_from_constants(
+    ::Vector,
+    ::Type{S},
+    rows,
+) where {S<:MOI.AbstractVectorSet}
+    return S(length(rows))
+end
+
+function set_from_constants(
+    ::Vector,
+    ::Type{S},
+    rows,
+) where {S<:MOI.AbstractSymmetricMatrixSetTriangle}
+    nnz = length(rows)
+    side_dimension = (-1 + sqrt(1 + 8nnz)) / 2
+    @assert side_dimension * (side_dimension + 1) == 2 * nnz
+    return S(Int(side_dimension))
+end
+
+function set_from_constants(
+    ::Vector,
+    ::Type{S},
+    rows,
+) where {S<:MOI.AbstractSymmetricMatrixSetSquare}
+    nnz = length(rows)
+    side_dimension = isqrt(nnz)
+    @assert length(rows) == side_dimension^2
+    return S(side_dimension)
+end
 
 function MOI.get(
     model::MatrixOfConstraints,
diff --git a/test/Utilities/matrix_of_constraints.jl b/test/Utilities/matrix_of_constraints.jl
index 9b0d6bc864..3519490396 100644
--- a/test/Utilities/matrix_of_constraints.jl
+++ b/test/Utilities/matrix_of_constraints.jl
@@ -49,6 +49,8 @@ MOI.Utilities.@product_of_sets(
     MOI.Nonnegatives,
     MOI.Nonpositives,
     MOI.SecondOrderCone,
+    MOI.PositiveSemidefiniteConeSquare,
+    MOI.PositiveSemidefiniteConeTriangle,
 )
 
 function _new_VectorSets()
@@ -398,6 +400,30 @@ function test_multicone()
     return
 end
 
+function test_matrix_sets_Triangle()
+    S = MOI.PositiveSemidefiniteConeTriangle
+    model = MOI.Utilities.Model{Int}()
+    x = MOI.add_variables(model, 3)
+    f = MOI.Utilities.operate(vcat, Int, (1 .* x)...)
+    c = MOI.add_constraint(model, f, S(2))
+    dest = _new_VectorSets()
+    map = MOI.copy_to(dest, model)
+    @test MOI.get(dest, MOI.ConstraintSet(), map[c]) == S(2)
+    return
+end
+
+function test_matrix_sets_Square()
+    S = MOI.PositiveSemidefiniteConeSquare
+    model = MOI.Utilities.Model{Int}()
+    x = MOI.add_variables(model, 4)
+    f = MOI.Utilities.operate(vcat, Int, (1 .* x)...)
+    c = MOI.add_constraint(model, f, S(2))
+    dest = _new_VectorSets()
+    map = MOI.copy_to(dest, model)
+    @test MOI.get(dest, MOI.ConstraintSet(), map[c]) == S(2)
+    return
+end
+
 end
 
 TestMatrixOfConstraints.runtests()