Within the individual phases of a DMAIC or DMADV project, Six Sigma utilizes many established quality-management tools that are also used outside of Six Sigma. The following table shows an overview of the main methods used.

• 5 Whys
• Analysis of variance
• ANOVA Gauge R&R
• Axiomatic design
• Business Process Mapping
• Cause & effects diagram (also known as fishbone or Ishikawa diagram)
• Chi-square test of independence and fits
• Control chart
• Correlation
• Cost-benefit analysis
• CTQ tree
• Design of experiments (DOE)
• Failure mode and effects analysis (FMEA )
• General linear model 
• Histograms
• Quality Function Deployment (QFD)
• Pareto chart
• Pick chart
• Process capability
• Quantitative marketing research through use of Enterprise Feedback Management (EFM) systems
• Regression analysis
• Root cause analysis (RCA)
• Run charts
• SIPOC analysis (Suppliers, Inputs, Process, Outputs, Customers)
• Taguchi methods
• Taguchi Loss Function
• TRIZ

Implementation roles

One key innovation of Six Sigma involves the "professionalizing" of quality management functions. Prior to Six Sigma, quality management in practice was largely relegated to the production floor and to statisticians in a separate quality department. Formal Six Sigma programs borrow martial arts ranking terminology to define a hierarchy (and career path) that cuts across all business functions.

Six Sigma identifies several key roles for its successful implementation.
• Executive Leadership includes the CEO and other members of top management. They are responsible for setting up a vision for Six Sigma implementation. They also empower the other role holders with the freedom and resources to explore new ideas for breakthrough improvements.
• Champions take responsibility for Six Sigma implementation across the organization in an integrated manner. The Executive Leadership draws them from upper management. Champions also act as mentors to Black Belts.
• Master Black Belts, identified by champions, act as in-house coaches on Six Sigma. They devote 100% of their time to Six Sigma. They assist champions and guide Black Belts and Green Belts. Apart from statistical tasks, they spend their time on ensuring consistent application of Six Sigma across various functions and departments.
• Black Belts operate under Master Black Belts to apply Six Sigma methodology to specific projects. They devote 100% of their time to Six Sigma. They primarily focus on Six Sigma project execution, whereas Champions and Master Black Belts focus on identifying projects/functions for Six Sigma.
• Green Belts are the employees who take up Six Sigma implementation along with their other job responsibilities, operating under the guidance of Black Belts.

Some organizations use additional belt colors, such as Yellow Belts, for employees that have basic training in Six Sigma tools.