The January Uprising (Polish: powstanie styczniowe; Lithuanian: 1863 metų sukilimas; Ukrainian: Січневе повстання; Russian: Польское восстание; Belarusian: Паўстанне 1863—1864 гадоў) was an insurrection principally in Russia's Kingdom of Poland aimed at the restoration of the Polish–Lithuanian Commonwealth. It began on 22 January 1863 and continued until the last insurgents were captured by the Russian forces in 1864.

It was the longest lasting insurgency in post-partition Poland. The conflict engaged all levels of society, and arguably had profound repercussions on contemporary international relations and ultimately provoked a social and ideological paradigm shift in national events that went on to have a decisive influence on the subsequent development of Polish society.A confluence of factors rendered the uprising inevitable in early 1863. The Polish nobility and urban bourgeois circles longed for the semi-autonomous status they had enjoyed in Congress Poland before the previous insurgency, a generation earlier in 1830, while youth encouraged by the success of the Italian independence movement urgently desired the same outcome. Russia had been weakened by its Crimean adventure and had introduced a more liberal attitude in its internal politics which encouraged Poland's underground National Government to plan an organised strike against their Russian occupiers no earlier than the Spring of 1863. They had not reckoned with Aleksander Wielopolski, the pro-Russian arch-conservative head of the civil administration in the Russian partition, who got wind of the plans. Wielopolski was aware that his fellow countrymen's fervent desire for independence was coming to a head, something he wanted to avoid at all costs. In an attempt to derail the Polish national movement, he brought forward to January the conscription of young Polish activists into the Imperial Russian Army (for 20-year service). That decision is what triggered the January Uprising of 1863, the very outcome Wielopolski had wanted to avoid.The rebellion by young Polish conscripts was soon joined by high-ranking Polish-Lithuanian officers and members of the political class. The insurrectionists, as yet ill-organised, were severely outnumbered and lacking sufficient foreign support, and were forced into hazardous guerrilla tactics. Reprisals were swift and ruthless. Public executions and deportations to Siberia eventually persuaded many Poles to abandon armed struggle. In addition, Tsar Alexander II hit the landed gentry hard, and as a result the whole economy, with a sudden decision in 1864 to finally abolish serfdom in Poland. The ensuing break-up of estates and destitution of many peasants convinced educated Poles to turn instead to the idea of "organic work", economic and cultural self-improvement.