Catholic doctrine supports some principles commonly associated with socialism—especially concern for the poor, solidarity, economic justice, and the duty to pursue the common good—but it does not endorse socialism as a complete ideology or system when it rejects private property, freedom, family, religion, or intermediate communities.

The Church teaches that:

• Private property is legitimate and rooted in human nature, so it may not simply be abolished or treated as theft.
• Property is not absolute: the wealthy have a serious moral duty to assist the poor and share their surplus with those in need.
• Solidarity is required: individuals and social institutions must contribute to the common good rather than pursue purely individual interests.
• Collectivism is rejected: the State must not replace the responsibility and initiative of individuals, families, churches, and other intermediate communities. This is the principle of subsidiarity—higher authorities should assist lower communities, not absorb them.

Pope Pius XI therefore taught that socialism, “if it remains truly Socialism,” cannot be reconciled with Catholic teaching because its understanding of society conflicts with Christian truth. This judgment concerns socialism as a comprehensive doctrine or movement, not every public policy sometimes called “socialist.”

Thus, a Catholic may support particular measures such as social assistance, labor protections, universal access to necessities, or progressive taxation, provided they respect human dignity, legitimate property, freedom, subsidiarity, and the common good. But Catholic doctrine does not support socialism understood as state collectivism, class warfare, atheistic materialism, or the abolition of private property. Modern political parties using the word “socialist” must therefore be judged by their actual principles and policies, not by the label alone.