This paper is concerned with the following nonlinear magnetic Schrödinger-Poisson type equation
$$\begin{array}{}
\displaystyle
\left\{
\begin{aligned}
&\Big(\frac{\epsilon}{i}\nabla-A(x)\Big)^{2}u+V(x)u+\epsilon^{-2}(\vert x\vert^{-1}\ast \vert u\vert^{2})u=f(|u|^{2})u+\vert u\vert^{4}u
\quad
\hbox{in }\mathbb{R}^3,\\
&u\in H^{1}(\mathbb{R}^{3}, \mathbb{C}),
\end{aligned}
\right.
\end{array}$$
where ϵ > 0, V : ℝ3 → ℝ and A : ℝ3 → ℝ3 are continuous potentials, f : ℝ → ℝ is a subcritical nonlinear term and is only continuous. Under a local assumption on the potential V, we use variational methods, penalization technique and Ljusternick-Schnirelmann theory to prove multiplicity and concentration of nontrivial solutions for ϵ > 0 small.