The exceedingly harsh terms of the Treaty of Brest-Litovsk. The treaty had caused even more economic hardship for the people of Russia, compounding the dire economic situation resulting from involvement in WWI and the backwards economic state of Russia even before the war. Evidence to support the harshness of the terms is that Russia were required to pay 3 billion roubles in war reparations to Germany, as well as giving up large swathes of territory, including Finland, Latvia, and - perhaps most significantly - the Ukraine, the 'bread basket' of Eastern Europe which had some of the most fertile land for growing crops. Since a large proportion of the population were peasants yet only a quarter of Russian land was good quality farmland, the loss of the Ukraine ensured more economic harship.

The defection of the Czech Legion. The Czech Legion had fought Austria alongside Russia throughout WWI and, as such, were deeply betrayed by Russia's withdrawal from the war, as it left them more vulnerable. They received permission to travel through Siberian using the Trans-Siberian Railway, but fighting broke out when some Bolsheviks attempted to arrest certain members of the Czech Legion. Anti-Bolshevik White forces soon joined the fighting and the conflict gradually developed into the Civil War.

The Whites were united only by their anti-Bolshevik sentiments. However, they were deeply divided politically, for example army officers who had supported the tsarist regime and Socialist Revolutionaries who had been forced out of the government by the Bolsheviks after opposing the terms of the Treaty of Brest-Litovsk found it very challenging to cooperate. This led to internal conflict within the White forces. There was a great variation and range in terms of the motivations of the Whites for fighting the Bolsheviks, which deepened the divisions between them.

The Bolsheviks had seized power by force in October 1917. In other words, the October Revolution had been a Bolshevik 'coup d'etat'. As such, those on the right of the political spectrum regarded the Bolsheviks as having no authority to rule, while those in the centre took issue with the way in which Lenin had disregarded the results of the election of November 1917 ("Elections prove nothing.") and forcibly closed the Constituent Assembly. Those on the left generally regarded the refusal of Lenin and the Bolsheviks to share power with the soviets as problematic, particularly considering they had come to power under the slogan, 'All Power to the Soviets'.

Certain groups were alienated by the Bolshevik regime, prompting them to join the White forces. For example, the 'exploiting classes' like businessmen and the bourgeoisie had been forbidden to vote in the 1918 Constitution, since the vote had been restricted merely to the 'toiling masses'. Businessmen and landowners had also suffered as a result of the Bolshevik policies of nationalisation of industry and land.

Some hoped for the reestablishment of the tsarist regime (although they did not necessarily wish for the reinstatement of Tsar Nicholas II himself). This included army officers who had prospered to an extent under the tsar.

The terms of the Treaty of Brest-Litovsk were resented by many, which encouraged anti-Bolshevik tendencies. Many felt the Bolsheviks had not addressed the major economic issues facing Russia and had in fact compounded the situation through the treaty.

The Kadets and more right-wing Socialist Revolutionaries resented the Bolsheviks for forcing them out of the government, while the Socialist Revolutionaries were also antagonised by Lenin's removal of them from government due to their opposition to the Treaty of Brest-Litovsk.

Opposition to the withdrawal of Russia from the fight against Germany in the First World War.

Some foreign powers - particularly Britain and France - feared the effect of Bolshevism on their own political systems due to the Bolsheviks' ambitions for international (permanent) revolution.

The nationalisation of industry by the Bolsheviks had negative consequences for foreign-owned businesses in Russia.

Foreign powers were annoyed by the Bolsheviks' repudiation of tsarist debts.