Noncommutative loops over Lie algebras and Lie groups We study noncommutative closures ("global deformations") of Lie algebras. For any Lie algebra $g$ sitting inside an associative algebra $A$ and any associative algebra $R$ we consider the $R$-loop algebra $(g,A)(R)$, which is the Lie subalgebra of $R\otimes A$ generated by $R\otimes g$. In most examples $A$ is the universal enveloping algebra o$g$. Our description of the loop algebra has a striking resemblance to the commutator expansions used by M. Kapranov in his approach to noncommutative geometry. We also associate with each $R$-loops algebras $(g,A)(R)$ a "noncommutative algebraic" group which naturally acts on $(g,A)(R)$ by conjugations and discuss a number of examples of such groups. This is joint work with A. Berenstein.