In the reign of King Rama V, the country's situation changed significantly. The country's development increased the number of government officers and rendered the old administrative regime obsolete. There arose a need to adjust the administrative regime, and in a speech King Rama V stated that: "...the administration regime we have been using is not sufficiently flexible. Especially now that our country has become much more developed than in the past. The existing administration cannot serve the greater demands of the country. As a result, we have the massive undertaking of adjusting the administration to keep abreast with the country's progress..."

Another important factor was the advent of colonialism which was expanding to the Far East during this period. Under colonial aggrandizement policies, Western powers such as Great Britain and France colonized Thailand's neighboring countries and tried to exploit Thailand. France, for instance, took the opportunity from Thailand's lack of an efficient government system and territorial protection measures to make a "Scientific expedition", using a border dispute as an excuse. After acquiring Vietnam, France assigned personnel to make a population and boundary survey. Since there were no official borders between Thailand and Vietnam, it was easy for the French to annex some parts within the Thai border to Vietnam. This pushed Thailand to make reforms to prevent a repetition of this kind of event.

Another factor leading to administrative reform was the wish of King Rama VI to abolish old practices that created oppression and injustice to the Thai people, that is, slavery and metropolitan customs (trial by means of torture). This intention can be found in his speech on slavery and retirement, "...I wish that things that are beneficial to the people could be constantly improved while old practices that are unfair should be abolished..."

Moreover, King Rama V wanted to introduce new aspects to the country's administration. For example, he founded the Council of State which was composed of 10-20 members with the King as the Head of the Council and the Privy Council which consisted of a flexible number of members depending on his will. In 113 R.E. (Ratanakosin Era) Rama V replaced the Councils with a Council of Ministers which was made up of more than 12 ministers or representatives and members appointed by the King. Also, local administration was one factor that contributed to the reforms. During the reign of King Rama IV, many Western countries conducted an amity treaty with Thailand which gave them extraterritorial rights. That is foreigners were allowed to set up consular courts to try their own nationals and their subjects outside of Thailand's judicial control. This was because Westerners regarded Thai laws and trial systems as undeveloped. These extraterritorial rights caused a lot of difficulties to the Thai administration system. King Rama V, therefore, intended to reorganise and improve the Legal system and Courts of Justice of the country to gain confidence from Westerners and eliminate the problems caused by extraterritorial rights. Thus, judicial reform took place during his reign as well.

Mr. Voradesh Chantason, a scholar, has outlined 7 major problems faced by Thailand at that time, which were motivating factors for reform, namely.

1. The backwardness of country's administration system which placed the nation's unity on a fragile basis. The ineffective and backward administration system, the overlapping of work, confusion of control and centralisation put national security at risk and opened the opportunity for intervention of Western colonialism.
2. Thailand's finance and taxation administration system did not support the development of the country or the power of the monarchy because it lacked a central agency that could control and administer the country's revenue effectively. The king was unable to supervise the officers in charge of taxation to make them comply with the rules.
3. The system of retainers caused the political problem of using retainers as source of political power to overthrow the King and thus created a threat to the throne and to the unity of the nation. Besides, the inability of retainers to accumulate wealth due to the labor service requirement impeded economic development, and the corruption of their masters ruined the benefits of the monarchy as well as the country as a whole.
4. The problem of slavery created oppression and injustice in society and indicated the uncivilized state of the country which was dangerous to national security if Westerners used slavery as an excuse to intervene to civilize and improve the quality of life of people in developing countries. Economically, Thailand's slavery was a labour system that obstructed the development of the economy and human resources.
5. Thailand military system was not efficient enough to defend the national interest or honor. It mainly relied on a retainer service to defend the Kingdom and splintered the control of people into groups, thereby putting the monarchy and national unity on an unstable footing and making the army lack unity, discipline, effective preparation and practice. Army registration was slow, leading to a problem in identifying the exact number of soldiers.
6. The flaws of the backward legal and judicial systems were that they were different to civilized countries and were unable to ensure justice was provided to locals and foreigners. Capital punishment and slow and prolonged trials did not accommodate commercial and social progress. Too many trial bodies, the scattered branching of courts into different departments, a long-standing bribery system and other problems that led to injustice and backwardness placed pressure on the country, caused administrative difficulties and obstructed development.
7. Educational problems: Before the reforms, a modern educational system did not exist. No specific agency was designated to be directly responsible for education. Limiting education to only royals and aristocrats generated injustice and deprived the majority of the population of the opportunity to develop their quality of life and deprived the country of efficient workers. This was an obstacle to development, depriving the country of defensive power and contributing to foreigners' contemptuous view of Thailand as a barbarous and backward nation.